Eckhard Bick - VISL

word-final 'r', especially in infinitives, approaches the zero-morpheme: *amá - amar
(to love), *agradecê - agradecer (to thank), *mulhé - mulher (woman).
The quantitatively most demanding problem, however, is faulty accentuation,
due to typist errors when compiling the corpus (the Borba-Ramsey corpus on the
European Corpus Initiative CD-ROM was not scanned or collected from pre-existing
electronic text, but typed), or to 8th-bit-ASCII losses in traffic accidents on the
information highway (where only English gets a safe ride). Removing or adding
accentuation may, however, lead to mistakes, where both the accentuated and the unaccentuated
word form represent perfectly normal lexical items, as in maca
(hammock), maça (club) and maçã (apple). Also, there might be ambiguity as to
which accent to add. Therefore, most of the accentuation heuristics module is only
used on otherwise unanalysable words. Safe bets are the adding of the til in word
final 'ao' and 'oes' (which are nearly unthinkable without the accent), yielding 'ão' and
'ões', whereas the change of 'c' into 'ç' before dark vowels is much more likely in the
suffix '-ção' (plural '-ções') than, say, in word-initial position.
Of the non-nasal accents in Portuguese, the grave accent only appears when
the preposition a is fused with pronouns whose first letter is 'a': à (=a a), às (=a as),
àquela (=a aquela). Since, on the tagging level, the parser has not yet enough
contextual knowledge to disambiguate the isolated pronoun from the misspelled
fused form a + pronoun, no accent-adding is attempted here.
The acute and circumflex accent spelling errors are handled by the tagger
module in the following way:
If there is no prior analysis, and if:
(a1) the word contains no accent, and only 1 vowel
-> add an acute accent to the vowel
-> if the word is still unanalysable, add a circumflex instead
(a2) the word contains no accent, and more than 1 vowel
-> look the word's potential stems up as unaccented root-forms ("R-forms") in the
lexicon.
Since the acute- and circumflex- accents in Portuguese - besides denoting vowel
opening in 'e' and 'o' - are used as stress markers, and since stress can change in
derivation, - accented potentially suffix-taking word stems (i.e. typically nouns and
adjectives 38 ) have "R-forms" (derivation root forms) entered in the lexicon, where
the accent has been removed. Ordinarily, these are intended only to be used in
combination with a stress-taking suffix, like '-ável' or '-inho'. In the spelling
correction module, however, this condition is suspended, and "R-forms" may be used
to recognise missing accent errors in suffix-less words. There are (acute- and
38 Verbs, too, combine with a number of suffixes, but all verbs' base forms (infinitives) have oxitonous stress, and since
accents in Portuguese are stress markers, no extra lexicon entry is necessary here.
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