hunspell - format of Hunspell dictionaries and affix files
Hunspell(1) Hunspell requires two files to define the way a language is
being spell checked: a dictionary file containing words and applicable flags,
and an affix file that specifies how these flags will control spell checking.
An optional file is the personal dictionary file.
A dictionary file (*.dic) contains a list of words, one per line. The first line
of the dictionaries (except personal dictionaries) contains the approximate
word count (for optimal hash memory size). Each word may optionally be
followed by a slash ("/") and one or more flags, which represents
the word attributes, for example affixes.
Note: Dictionary words can contain also slashes when escaped like "\/"
syntax.
It's worth to add not only words, but word pairs to the dictionary to get
correct suggestions for common misspellings with missing space, as in the
following example, for the bad "alot" and "inspite" (see
also "REP" and field "ph:" about correct suggestions for
common misspellings):
Personal dictionaries are simple word lists. Asterisk at the first character
position signs prohibition. A second word separated by a slash sets the
affixation.
In this example, "foo" and "Foo" are personal words, plus
Foo will be recognized with affixes of Simpson (Foo's etc.) and bar is a
forbidden word.
Dictionary file:
The flags B and A specify attributes of these words.
Affix file:
SET UTF-8
TRY esianrtolcdugmphbyfvkwzESIANRTOLCDUGMPHBYFVKWZ'
REP 2
REP f ph
REP ph f
PFX A Y 1
PFX A 0 re .
SFX B Y 2
SFX B 0 ed [^y]
SFX B y ied y
In the affix file, prefix A and suffix B have been defined. Flag A defines a
`re-' prefix. Class B defines two `-ed' suffixes. First B suffix can be added
to a word if the last character of the word isn't `y'. Second suffix can be
added to the words terminated with an `y'.
All accepted words with this dictionary and affix combination are:
"hello", "try", "tried", "work",
"worked", "rework", "reworked".
Hunspell source distribution contains more than 80 examples for option usage.
- SET encoding
- Set character encoding of words and morphemes in affix and
dictionary files. Possible values: UTF-8, ISO8859-1 - ISO8859-10,
ISO8859-13 - ISO8859-15, KOI8-R, KOI8-U, cp1251, ISCII-DEVANAGARI.
- FLAG value
- Set flag type. Default type is the extended ASCII (8-bit)
character. `UTF-8' parameter sets UTF-8 encoded Unicode character flags.
The `long' value sets the double extended ASCII character flag type, the
`num' sets the decimal number flag type. Decimal flags numbered from 1 to
65000, and in flag fields are separated by comma. BUG: UTF-8 flag type
doesn't work on ARM platform.
- COMPLEXPREFIXES
- Set twofold prefix stripping (but single suffix stripping)
eg. for morphologically complex languages with right-to-left writing
system.
- LANG langcode
- Set language code for language-specific functions of
Hunspell. Use it to activate special casing of Azeri (LANG az), Turkish
(LANG tr) and Crimean Tatar (LANG crh), also not generalized
syllable-counting compounding rules of Hungarian (LANG hu).
- IGNORE characters
- Sets characters to ignore dictionary words, affixes and
input words. Useful for optional characters, as Arabic (harakat) or Hebrew
(niqqud) diacritical marks (see tests/ignore.* test dictionary in Hunspell
distribution).
- AF number_of_flag_vector_aliases
- AF flag_vector
- Hunspell can substitute affix flag sets with ordinal
numbers in affix rules (alias compression, see makealias tool). First
example with alias compression:
AF definitions in the affix file:
It is equivalent of the following dic file:
See also tests/alias* examples of the source distribution.
Note I: If affix file contains the FLAG parameter, define it before the AF
definitions.
Note II: Use makealias utility in Hunspell distribution to compress aff and dic
files.
- AM number_of_morphological_aliases
- AM morphological_fields
- Hunspell can substitute also morphological data with
ordinal numbers in affix rules (alias compression). See tests/alias*
examples.
Suggestion parameters can optimize the default n-gram (similarity search in the
dictionary words based on the common 1, 2, 3, 4-character length common
character-sequences), character swap and deletion suggestions of Hunspell. REP
is suggested to fix the typical and especially bad language specific bugs,
because the REP suggestions have the highest priority in the suggestion list.
PHONE is for languages with not pronunciation based orthography.
For short common misspellings, it's important to use the ph: field (see later)
to give the best suggestions.
- KEY characters_separated_by_vertical_line_optionally
- Hunspell searches and suggests words with one different
character replaced by a neighbor KEY character. Not neighbor characters in
KEY string separated by vertical line characters. Suggested KEY parameters
for QWERTY and Dvorak keyboard layouts:
KEY qwertyuiop|asdfghjkl|zxcvbnm
KEY pyfgcrl|aeouidhtns|qjkxbmwvz
Using the first QWERTY layout, Hunspell suggests "nude" and
"node" for "*nide". A character may have more neighbors,
too:
KEY qwertzuop|yxcvbnm|qaw|say|wse|dsx|sy|edr|fdc|dx|rft|gfv|fc|tgz|hgb|gv|zhu|jhn|hb|uji|kjm|jn|iko|lkm
- TRY characters
- Hunspell can suggest right word forms, when they differ
from the bad input word by one TRY character. The parameter of TRY is case
sensitive.
- NOSUGGEST flag
- Words signed with NOSUGGEST flag are not suggested (but
still accepted when typed correctly). Proposed flag for vulgar and obscene
words (see also SUBSTANDARD).
- MAXCPDSUGS num
- Set max. number of suggested compound words generated by
compound rules. The number of the suggested compound words may be greater
from the same 1-character distance type.
- MAXNGRAMSUGS num
- Set max. number of n-gram suggestions. Value 0 switches off
the n-gram suggestions (see also MAXDIFF).
- MAXDIFF [0-10]
- Set the similarity factor for the n-gram based suggestions
(5 = default value; 0 = fewer n-gram suggestions, but min. 1; 10 =
MAXNGRAMSUGS n-gram suggestions).
- ONLYMAXDIFF
- Remove all bad n-gram suggestions (default mode keeps one,
see MAXDIFF).
- NOSPLITSUGS
- Disable word suggestions with spaces.
- SUGSWITHDOTS
- Add dot(s) to suggestions, if input word terminates in
dot(s). (Not for LibreOffice dictionaries, because LibreOffice has an
automatic dot expansion mechanism.)
- REP number_of_replacement_definitions
- REP what replacement
- This table specifies modifications to try first. First REP
is the header of this table and one or more REP data line are following
it. With this table, Hunspell can suggest the right forms for the typical
spelling mistakes when the incorrect form differs by more than 1 letter
from the right form (see also "ph:"). The search string supports
the regex boundary signs (^ and $). For example a possible English
replacement table definition to handle misspelled consonants:
REP 5
REP f ph
REP ph f
REP tion$ shun
REP ^cooccurr co-occurr
REP ^alot$ a_lot
Note I: It's very useful to define replacements for the most typical
one-character mistakes, too: with REP you can add higher priority to a subset
of the TRY suggestions (suggestion list begins with the REP suggestions).
Note II: Suggesting separated words, specify spaces with underlines:
REP 1
REP onetwothree one_two_three
Note III: Replacement table can be used for a stricter compound word checking
with the option CHECKCOMPOUNDREP.
- MAP number_of_map_definitions
- MAP
string_of_related_chars_or_parenthesized_character_sequences
- We can define language-dependent information on characters
and character sequences that should be considered related (i.e. nearer
than other chars not in the set) in the affix file (.aff) by a map table.
With this table, Hunspell can suggest the right forms for words, which
incorrectly choose the wrong letter or letter groups from a related set
more than once in a word (see REP).
For example a possible mapping could be for the German umlauted ü
versus the regular u; the word Frühstück really should be
written with umlauted u's and not regular ones
Use parenthesized groups for character sequences (eg. for composed Unicode
characters):
MAP 3
MAP ß(ss) (character sequence)
MAP fi(fi) ("fi" compatibility characters for Unicode fi ligature)
MAP (ọ́)o (composed Unicode character: ó with bottom dot)
- PHONE number_of_phone_definitions
- PHONE what replacement
- PHONE uses a table-driven phonetic transcription algorithm
borrowed from Aspell. It is useful for languages with not pronunciation
based orthography. You can add a full alphabet conversion and other rules
for conversion of special letter sequences. For detailed documentation see
http://aspell.net/man-html/Phonetic-Code.html. Note: Multibyte UTF-8
characters have not worked with bracket expression yet. Dash expression
has signed bytes and not UTF-8 characters yet.
- WARN flag
- This flag is for rare words, which are also often spelling
mistakes, see option -r of command line Hunspell and FORBIDWARN.
- FORBIDWARN
- Words with flag WARN aren't accepted by the spell checker
using this parameter.
- BREAK number_of_break_definitions
- BREAK character_or_character_sequence
- Define new break points for breaking words and checking
word parts separately. Use ^ and $ to delete characters at end and start
of the word. Rationale: useful for compounding with joining character or
strings (for example, hyphen in English and German or hyphen and n-dash in
Hungarian). Dashes are often bad break points for tokenization, because
compounds with dashes may contain not valid parts, too.) With BREAK,
Hunspell can check both side of these compounds, breaking the words at
dashes and n-dashes:
BREAK 2
BREAK -
BREAK -- # n-dash
Breaking are recursive, so foo-bar, bar-foo and foo-foo
--bar-bar would
be valid compounds. Note: The default word break of Hunspell is equivalent of
the following BREAK definition:
BREAK 3
BREAK -
BREAK ^-
BREAK -$
Hunspell doesn't accept the "-word" and "word-" forms by
this BREAK definition:
Switching off the default values:
Note II: COMPOUNDRULE is better for handling dashes and other compound joining
characters or character strings. Use BREAK, if you want to check words with
dashes or other joining characters and there is no time or possibility to
describe precise compound rules with COMPOUNDRULE (COMPOUNDRULE handles only
the suffixation of the last word part of a compound word).
Note III: For command line spell checking of words with extra characters, set
WORDCHARS parameters: WORDCHARS -
-- (see tests/break.*) example
- COMPOUNDRULE number_of_compound_definitions
- COMPOUNDRULE compound_pattern
- Define custom compound patterns with a regex-like syntax.
The first COMPOUNDRULE is a header with the number of the following
COMPOUNDRULE definitions. Compound patterns consist compound flags,
parentheses, star and question mark meta characters. A flag followed by a
`*' matches a word sequence of 0 or more matches of words signed with this
compound flag. A flag followed by a `?' matches a word sequence of 0 or 1
matches of a word signed with this compound flag. See tests/compound*.*
examples.
Note: en_US dictionary of OpenOffice.org uses COMPOUNDRULE for ordinal
number recognition (1st, 2nd, 11th, 12th, 22nd, 112th, 1000122nd etc.).
Note II: In the case of long and numerical flag types use only parenthesized
flags: (1500)*(2000)?
Note III: COMPOUNDRULE flags work completely separately from the compounding
mechanisms using COMPOUNDFLAG, COMPOUNDBEGIN, etc. compound flags. (Use
these flags on different entries for words).
- COMPOUNDMIN num
- Minimum length of words used for compounding. Default value
is 3 letters.
- COMPOUNDFLAG flag
- Words signed with COMPOUNDFLAG may be in compound words
(except when word shorter than COMPOUNDMIN). Affixes with COMPOUNDFLAG
also permits compounding of affixed words.
- COMPOUNDBEGIN flag
- Words signed with COMPOUNDBEGIN (or with a signed affix)
may be first elements in compound words.
- COMPOUNDLAST flag
- Words signed with COMPOUNDLAST (or with a signed affix) may
be last elements in compound words.
- COMPOUNDMIDDLE flag
- Words signed with COMPOUNDMIDDLE (or with a signed affix)
may be middle elements in compound words.
- ONLYINCOMPOUND flag
- Suffixes signed with ONLYINCOMPOUND flag may be only inside
of compounds (Fuge-elements in German, fogemorphemes in Swedish).
ONLYINCOMPOUND flag works also with words (see tests/onlyincompound.*).
Note: also valuable to flag compounding parts which are not correct as a
word by itself.
- COMPOUNDPERMITFLAG flag
- Prefixes are allowed at the beginning of compounds,
suffixes are allowed at the end of compounds by default. Affixes with
COMPOUNDPERMITFLAG may be inside of compounds.
- COMPOUNDFORBIDFLAG flag
- Suffixes with this flag forbid compounding of the affixed
word. Dictionary words with this flag are removed from the beginning and
middle of compound words, overriding the effect of
COMPOUNDPERMITFLAG.
- COMPOUNDMORESUFFIXES
- Allow twofold suffixes within compounds.
- COMPOUNDROOT flag
- COMPOUNDROOT flag signs the compounds in the dictionary
(Now it is used only in the Hungarian language specific code).
- COMPOUNDWORDMAX number
- Set maximum word count in a compound word. (Default is
unlimited.)
- CHECKCOMPOUNDDUP
- Forbid word duplication in compounds (e.g. foofoo).
- CHECKCOMPOUNDREP
- Forbid compounding, if the (usually bad) compound word may
be a non-compound word with a REP fault. Useful for languages with
`compound friendly' orthography.
- CHECKCOMPOUNDCASE
- Forbid upper case characters at word boundaries in
compounds.
- CHECKCOMPOUNDTRIPLE
- Forbid compounding, if compound word contains triple
repeating letters (e.g. foo|ox or xo|oof). Bug: missing multi-byte
character support in UTF-8 encoding (works only for 7-bit ASCII
characters).
- SIMPLIFIEDTRIPLE
- Allow simplified 2-letter forms of the compounds forbidden
by CHECKCOMPOUNDTRIPLE. It's useful for Swedish and Norwegian (and for the
old German orthography: Schiff|fahrt -> Schiffahrt).
- CHECKCOMPOUNDPATTERN
number_of_checkcompoundpattern_definitions
- CHECKCOMPOUNDPATTERN endchars[/flag] beginchars[/flag]
[replacement]
- Forbid compounding, if the first word in the compound ends
with endchars, and next word begins with beginchars and (optionally) they
have the requested flags. The optional replacement parameter allows
simplified compound form.
The special "endchars" pattern 0 (zero) limits the rule to the
unmodified stems (stems and stems with zero affixes):
CHECKCOMPOUNDPATTERN 0/x /y
Note: COMPOUNDMIN doesn't work correctly with the compound word alternation, so
it may need to set COMPOUNDMIN to lower value.
- FORCEUCASE flag
- Last word part of a compound with flag FORCEUCASE forces
capitalization of the whole compound word. Eg. Dutch word
"straat" (street) with FORCEUCASE flags will allowed only in
capitalized compound forms, according to the Dutch spelling rules for
proper names.
- COMPOUNDSYLLABLE max_syllable vowels
- Need for special compounding rules in Hungarian. First
parameter is the maximum syllable number, that may be in a compound, if
words in compounds are more than COMPOUNDWORDMAX. Second parameter is the
list of vowels (for calculating syllables).
- SYLLABLENUM flags
- Need for special compounding rules in Hungarian.
- PFX flag cross_product number
- PFX flag stripping prefix [condition
[morphological_fields...]]
- SFX flag cross_product number
- SFX flag stripping suffix [condition
[morphological_fields...]]
- An affix is either a prefix or a suffix attached to root
words to make other words. We can define affix classes with arbitrary
number affix rules. Affix classes are signed with affix flags. The first
line of an affix class definition is the header. The fields of an affix
class header:
(0) Option name (PFX or SFX)
(1) Flag (name of the affix class)
(2) Cross product (permission to combine prefixes and suffixes). Possible
values: Y (yes) or N (no)
(3) Line count of the following rules.
Fields of an affix rules:
(0) Option name
(1) Flag
(2) stripping characters from beginning (at prefix rules) or end (at suffix
rules) of the word
(3) affix (optionally with flags of continuation classes, separated by a
slash)
(4) condition.
Zero stripping or affix are indicated by zero. Zero condition is indicated
by dot. Condition is a simplified, regular expression-like pattern, which
must be met before the affix can be applied. (Dot signs an arbitrary
character. Characters in braces sign an arbitrary character from the
character subset. Dash hasn't got special meaning, but circumflex (^) next
the first brace sets the complementer character set.)
(5) Optional morphological fields separated by spaces or tabulators.
- CIRCUMFIX flag
- Affixes signed with CIRCUMFIX flag may be on a word when
this word also has a prefix with CIRCUMFIX flag and vice versa (see
circumfix.* test files in the source distribution).
- FORBIDDENWORD flag
- This flag signs forbidden word form. Because affixed forms
are also forbidden, we can subtract a subset from set of the accepted
affixed and compound words. Note: usefull to forbid erroneous words,
generated by the compounding mechanism.
- FULLSTRIP
- With FULLSTRIP, affix rules can strip full words, not only
one less characters, before adding the affixes, see fullstrip.* test files
in the source distribution). Note: conditions may be word length without
FULLSTRIP, too.
- KEEPCASE flag
- Forbid uppercased and capitalized forms of words signed
with KEEPCASE flags. Useful for special orthographies (measurements and
currency often keep their case in uppercased texts) and writing systems
(e.g. keeping lower case of IPA characters). Also valuable for words
erroneously written in the wrong case.
Note: With CHECKSHARPS declaration, words with sharp s and KEEPCASE flag may
be capitalized and uppercased, but uppercased forms of these words may not
contain sharp s, only SS. See germancompounding example in the tests
directory of the Hunspell distribution.
- ICONV number_of_ICONV_definitions
- ICONV pattern pattern2
- Define input conversion table. Note: useful to convert one
type of quote to another one, or change ligature.
- OCONV number_of_OCONV_definitions
- OCONV pattern pattern2
- Define output conversion table.
- LEMMA_PRESENT flag
- Deprecated. Use "st:" field instead of
LEMMA_PRESENT.
- NEEDAFFIX flag
- This flag signs virtual stems in the dictionary, words only
valid when affixed. Except, if the dictionary word has a homonym or a zero
affix. NEEDAFFIX works also with prefixes and prefix + suffix combinations
(see tests/needaffix5.*).
- PSEUDOROOT flag
- Deprecated. (Former name of the NEEDAFFIX option.)
- SUBSTANDARD flag
- SUBSTANDARD flag signs affix rules and dictionary words
(allomorphs) not used in morphological generation and root words removed
from suggestion. See also NOSUGGEST.
- WORDCHARS characters
- WORDCHARS extends tokenizer of Hunspell command line
interface with additional word character. For example, dot, dash, n-dash,
numbers, percent sign are word character in Hungarian.
- CHECKSHARPS
- SS letter pair in uppercased (German) words may be upper
case sharp s (ß). Hunspell can handle this special casing with the
CHECKSHARPS declaration (see also KEEPCASE flag and
tests/germancompounding example) in both spelling and suggestion.
Hunspell's dictionary items and affix rules may have optional space or tabulator
separated morphological description fields, started with 3-character (two
letters and a colon) field IDs:
word/flags po:noun is:nom
Example: We define a simple resource with morphological informations, a
derivative suffix (ds:) and a part of speech category (po:):
Affix file:
SFX X Y 1
SFX X 0 able . ds:able
Dictionary file:
Test file:
Test:
$ analyze test.aff test.dic test.txt
> drink
analyze(drink) = po:verb
stem(drink) = po:verb
> drinkable
analyze(drinkable) = po:verb ds:able
stem(drinkable) = drinkable
You can see in the example, that the analyzer concatenates the morphological
fields in
item and arrangement style.
Default morphological and other IDs (used in suggestion, stemming and
morphological generation):
- ph:
- Alternative transliteration for better suggestions, ie.
misspellings related to the special orthography and pronunciation of the
word. The best way to handle common misspellings, so it's worth to add ph:
field to the most affected few thousand dictionary words (or word pairs
etc.) to get correct suggestions for their misspellings.
For example:
Wednesday ph:wendsay ph:wensday
Marseille ph:maarsayl
Hunspell adds all ph: transliterations to the inner REP table, so it will always
suggest the correct word for the specified misspellings with the highest
priority.
The previous example is equivalent of the following REP definition:
REP 6
REP wendsay Wednesday
REP Wendsay Wednesday
REP wensday Wednesday
REP Wensday Wednesday
REP maarsayl Marseille
REP Maarsayl Marseille
The asterisk at the end of the ph: pattern means stripping the terminating
character both from the pattern and the word in the associated REP rule:
will result
REP rule, resulting the following correct suggestions
*prity -> pretty
*pritier -> prettier
*pritiest -> prettiest
Moreover, ph: fields can handle suggestions with more than two words, also
different suggestions for the same misspelling:
do not know ph:dunno
don't know ph:dunno
results
*dunno -> do not know, don't know
Note: if available, ph: is used in n-gram similarity, too.
The ASCII arrow "->" in a ph: pattern means a REP rule (see REP),
creating arbitrary replacement rule associated to the dictionary item:
happy/B ph:hepy ph:hepi->happi
results
*hepy -> happy
*hepiest -> happiest
- st:
- Stem. Optional: default stem is the dictionary item in
morphological analysis. Stem field is useful for virtual stems (dictionary
words with NEEDAFFIX flag) and morphological exceptions instead of new,
single used morphological rules.
feet st:foot is:plural
mice st:mouse is:plural
teeth st:tooth is:plural
Word forms with multiple stems need multiple dictionary items:
lay po:verb st:lie is:past_2
lay po:verb is:present
lay po:noun
- al:
- Allomorph(s). A dictionary item is the stem of its
allomorphs. Morphological generation needs stem, allomorph and affix
fields.
sing al:sang al:sung
sang st:sing
sung st:sing
- po:
- Part of speech category.
- ds:
- Derivational suffix(es). Stemming doesn't remove
derivational suffixes. Morphological generation depends on the order of
the suffix fields.
In affix rules:
SFX Y Y 1
SFX Y 0 ly . ds:ly_adj
In the dictionary:
ably st:able ds:ly_adj
able al:ably
- is:
- Inflectional suffix(es). All inflectional suffixes are
removed by stemming. Morphological generation depends on the order of the
suffix fields.
- ts:
- Terminal suffix(es). Terminal suffix fields are
inflectional suffix fields "removed" by additional (not
terminal) suffixes.
Useful for zero morphemes and affixes removed by splitting rules.
SFX D Y 2
SFX D 0 ed . is:past_1
SFX D 0 ed . is:past_2
Typical example of the terminal suffix is the zero morpheme of the nominative
case.
- sp:
- Surface prefix. Temporary solution for adding prefixes to
the stems and generated word forms. See tests/morph.* example.
- pa:
- Parts of the compound words. Output fields of morphological
analysis for stemming.
- dp:
- Planned: derivational prefix.
- ip:
- Planned: inflectional prefix.
- tp:
- Planned: terminal prefix.
Ispell's original algorithm strips only one suffix. Hunspell can strip another
one yet (or a plus prefix in COMPLEXPREFIXES mode).
The twofold suffix stripping is a significant improvement in handling of immense
number of suffixes, that characterize agglutinative languages.
A second `s' suffix (affix class Y) will be the continuation class of the suffix
`able' in the following example:
SFX Y Y 1
SFX Y 0 s .
SFX X Y 1
SFX X 0 able/Y .
Dictionary file:
Test file:
drink
drinkable
drinkables
Test:
$ hunspell -m -d test <test.txt
drink st:drink
drinkable st:drink fl:X
drinkables st:drink fl:X fl:Y
Theoretically with the twofold suffix stripping needs only the square root of
the number of suffix rules, compared with a Hunspell implementation. In our
practice, we could have elaborated the Hungarian inflectional morphology with
twofold suffix stripping.
Hunspell can handle more than 65000 affix classes. There are three new syntax
for giving flags in affix and dictionary files.
FLAG long command sets 2-character flags:
FLAG long
SFX Y1 Y 1
SFX Y1 0 s 1
Dictionary record with the Y1, Z3, F? flags:
FLAG num command sets numerical flags separated by comma:
FLAG num
SFX 65000 Y 1
SFX 65000 0 s 1
Dictionary example:
The third one is the Unicode character flags.
Hunspell's dictionary can contain repeating elements that are homonyms:
work/A po:verb
work/B po:noun
An affix file:
SFX A Y 1
SFX A 0 s . sf:sg3
SFX B Y 1
SFX B 0 s . is:plur
Test file:
Test:
$ hunspell -d test -m <testwords
work st:work po:verb is:sg3
work st:work po:noun is:plur
This feature also gives a way to forbid illegal prefix/suffix combinations.
An interesting side-effect of multi-step stripping is, that the appropriate
treatment of circumfixes now comes for free. For instance, in Hungarian,
superlatives are formed by simultaneous prefixation of
leg- and
suffixation of
-bb to the adjective base. A problem with the one-level
architecture is that there is no way to render lexical licensing of particular
prefixes and suffixes interdependent, and therefore incorrect forms are
recognized as valid, i.e. *
legvén =
leg +
vén `old'. Until the introduction of clusters, a special
treatment of the superlative had to be hardwired in the earlier
HunSpell code. This may have been legitimate for a single case, but in
fact prefix--suffix dependences are ubiquitous in category-changing
derivational patterns (cf. English
payable,
non-payable but
*non-pay or
drinkable,
undrinkable but
*undrink).
In simple words, here, the prefix
un- is legitimate only if the base
drink is suffixed with
-able. If both these patters are handled
by on-line affix rules and affix rules are checked against the base only,
there is no way to express this dependency and the system will necessarily
over- or undergenerate.
In next example, suffix class R have got a prefix `continuation' class (class
P).
PFX P Y 1
PFX P 0 un . [prefix_un]+
SFX S Y 1
SFX S 0 s . +PL
SFX Q Y 1
SFX Q 0 s . +3SGV
SFX R Y 1
SFX R 0 able/PS . +DER_V_ADJ_ABLE
Dictionary:
2
drink/RQ [verb]
drink/S [noun]
Morphological analysis:
> drink
drink[verb]
drink[noun]
> drinks
drink[verb]+3SGV
drink[noun]+PL
> drinkable
drink[verb]+DER_V_ADJ_ABLE
> drinkables
drink[verb]+DER_V_ADJ_ABLE+PL
> undrinkable
[prefix_un]+drink[verb]+DER_V_ADJ_ABLE
> undrinkables
[prefix_un]+drink[verb]+DER_V_ADJ_ABLE+PL
> undrink
Unknown word.
> undrinks
Unknown word.
Conditional affixes implemented by a continuation class are not enough for
circumfixes, because a circumfix is one affix in morphology. We also need
CIRCUMFIX option for correct morphological analysis.
# circumfixes: ~ obligate prefix/suffix combinations
# superlative in Hungarian: leg- (prefix) AND -bb (suffix)
# nagy, nagyobb, legnagyobb, legeslegnagyobb
# (great, greater, greatest, most greatest)
CIRCUMFIX X
PFX A Y 1
PFX A 0 leg/X .
PFX B Y 1
PFX B 0 legesleg/X .
SFX C Y 3
SFX C 0 obb . +COMPARATIVE
SFX C 0 obb/AX . +SUPERLATIVE
SFX C 0 obb/BX . +SUPERSUPERLATIVE
Dictionary:
Analysis:
> nagy
nagy[MN]
> nagyobb
nagy[MN]+COMPARATIVE
> legnagyobb
nagy[MN]+SUPERLATIVE
> legeslegnagyobb
nagy[MN]+SUPERSUPERLATIVE
Allowing free compounding yields decrease in precision of recognition, not to
mention stemming and morphological analysis. Although lexical switches are
introduced to license compounding of bases by
Ispell, this proves not
to be restrictive enough. For example:
# affix file
COMPOUNDFLAG X
With this resource,
foobar and
barfoo also are accepted words.
This has been improved upon with the introduction of direction-sensitive
compounding, i.e., lexical features can specify separately whether a base can
occur as leftmost or rightmost constituent in compounds. This, however, is
still insufficient to handle the intricate patterns of compounding, not to
mention idiosyncratic (and language specific) norms of hyphenation.
The
Hunspell algorithm currently allows any affixed form of words, which
are lexically marked as potential members of compounds.
Hunspell
improved this, and its recursive compound checking rules makes it possible to
implement the intricate spelling conventions of Hungarian compounds. For
example, using COMPOUNDWORDMAX, COMPOUNDSYLLABLE, COMPOUNDROOT, SYLLABLENUM
options can be set the noteworthy Hungarian `6-3' rule. Further example in
Hungarian, derivate suffixes often modify compounding properties. Hunspell
allows the compounding flags on the affixes, and there are two special flags
(COMPOUNDPERMITFLAG and (COMPOUNDFORBIDFLAG) to permit or prohibit compounding
of the derivations.
Suffixes with this flag forbid compounding of the affixed word.
We also need several Hunspell features for handling German compounding:
# German compounding
# set language to handle special casing of German sharp s
LANG de_DE
# compound flags
COMPOUNDBEGIN U
COMPOUNDMIDDLE V
COMPOUNDEND W
# Prefixes are allowed at the beginning of compounds,
# suffixes are allowed at the end of compounds by default:
# (prefix)?(root)+(affix)?
# Affixes with COMPOUNDPERMITFLAG may be inside of compounds.
COMPOUNDPERMITFLAG P
# for German fogemorphemes (Fuge-element)
# Hint: ONLYINCOMPOUND is not required everywhere, but the
# checking will be a little faster with it.
ONLYINCOMPOUND X
# forbid uppercase characters at compound word bounds
CHECKCOMPOUNDCASE
# for handling Fuge-elements with dashes (Arbeits-)
# dash will be a special word
COMPOUNDMIN 1
WORDCHARS -
# compound settings and fogemorpheme for `Arbeit'
SFX A Y 3
SFX A 0 s/UPX .
SFX A 0 s/VPDX .
SFX A 0 0/WXD .
SFX B Y 2
SFX B 0 0/UPX .
SFX B 0 0/VWXDP .
# a suffix for `Computer'
SFX C Y 1
SFX C 0 n/WD .
# for forbid exceptions (*Arbeitsnehmer)
FORBIDDENWORD Z
# dash prefix for compounds with dash (Arbeits-Computer)
PFX - Y 1
PFX - 0 -/P .
# decapitalizing prefix
# circumfix for positioning in compounds
PFX D Y 29
PFX D A a/PX A
PFX D Ä ä/PX Ä
.
.
PFX D Y y/PX Y
PFX D Z z/PX Z
Example dictionary:
4
Arbeit/A-
Computer/BC-
-/W
Arbeitsnehmer/Z
Accepted compound compound words with the previous resource:
Computer
Computern
Arbeit
Arbeits-
Computerarbeit
Computerarbeits-
Arbeitscomputer
Arbeitscomputern
Computerarbeitscomputer
Computerarbeitscomputern
Arbeitscomputerarbeit
Computerarbeits-Computer
Computerarbeits-Computern
Not accepted compoundings:
computer
arbeit
Arbeits
arbeits
ComputerArbeit
ComputerArbeits
Arbeitcomputer
ArbeitsComputer
Computerarbeitcomputer
ComputerArbeitcomputer
ComputerArbeitscomputer
Arbeitscomputerarbeits
Computerarbeits-computer
Arbeitsnehmer
This solution is still not ideal, however, and will be replaced by a
pattern-based compound-checking algorithm which is closely integrated with
input buffer tokenization. Patterns describing compounds come as a separate
input resource that can refer to high-level properties of constituent parts
(e.g. the number of syllables, affix flags, and containment of hyphens). The
patterns are matched against potential segmentations of compounds to assess
wellformedness.
Both
Ispell and
Myspell use 8-bit ASCII character encoding, which
is a major deficiency when it comes to scalability. Although a language like
Hungarian has a standard ASCII character set (ISO 8859-2), it fails to allow a
full implementation of Hungarian orthographic conventions. For instance, the
'--' symbol (n-dash) is missing from this character set contrary to the fact
that it is not only the official symbol to delimit parenthetic clauses in the
language, but it can be in compound words as a special 'big' hyphen.
MySpell has got some 8-bit encoding tables, but there are languages without
standard 8-bit encoding, too. For example, a lot of African languages have
non-latin or extended latin characters.
Similarly, using the original spelling of certain foreign names like
Ångström or
Molière is encouraged by the
Hungarian spelling norm, and, since characters 'Å' and 'è' are
not part of ISO 8859-2, when they combine with inflections containing
characters only in ISO 8859-2 (like elative
-ből,
allative
-től or delative
-ről with double acute),
these result in words (like
Ångströmről or
Molière-től.) that can not be encoded using any single
ASCII encoding scheme.
The problems raised in relation to 8-bit ASCII encoding have long been
recognized by proponents of Unicode. It is clear that trading efficiency for
encoding-independence has its advantages when it comes a truly multi-lingual
application. There is implemented a memory and time efficient Unicode handling
in Hunspell. In non-UTF-8 character encodings Hunspell works with the original
8-bit strings. In UTF-8 encoding, affixes and words are stored in UTF-8,
during the analysis are handled in mostly UTF-8, under condition checking and
suggestion are converted to UTF-16. Unicode text analysis and spell checking
have a minimal (0-20%) time overhead and minimal or reasonable memory overhead
depends from the language (its UTF-8 encoding and affixation).
Aspell dictionaries can be easily converted into hunspell. Conversion steps:
dictionary (xx.cwl -> xx.wl):
preunzip xx.cwl
wc -l < xx.wl > xx.dic
cat xx.wl >> xx.dic
affix file
If the affix file exists, copy it:
cp xx_affix.dat xx.aff
If not, create it with the suitable character encoding (see xx.dat)
echo "SET ISO8859-x" > xx.aff
or
echo "SET UTF-8" > xx.aff
It's useful to add a TRY option with the characters of the dictionary with
frequency order to set edit distance suggestions:
echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff
Aspell dictionaries can be easily converted into hunspell. Conversion steps:
dictionary (xx.cwl -> xx.wl):
preunzip xx.cwl
wc -l < xx.wl > xx.dic
cat xx.wl >> xx.dic
affix file
If the affix file exists, copy it:
cp xx_affix.dat xx.aff
If not, create it with the suitable character encoding (see xx.dat)
echo "SET ISO8859-x" > xx.aff
or
echo "SET UTF-8" > xx.aff
It's useful to add a TRY option with the characters of the dictionary with
frequency order to set edit distance suggestions:
echo "TRY qwertzuiopasdfghjklyxcvbnmQWERTZUIOPASDFGHJKLYXCVBNM" >>xx.aff
hunspell (1), ispell (1), ispell (4)