Eckhard Bick - VISL

(iii) corvos-marinhos
"corvo-marinho" N M P
(iv) Estados=Unidos
"Estados=Unidos" PROP M P
(2) offers examples for derivational tags (DERP for prefixes and DERS for suffixes),
as well as polylexical word boundaries (the '=' sign in (iv) is introduced by the tagger
to mark a non-hyphen polylexical link). Also purely orthographic or procedural
information can be added to the tag list, like for capitalisation or for
use of the heuristics module 7 .
The morphological analyser constitutes the lowest level of the PALAVRAS
parsing system, and feeds its output to Constraint Grammar morphological
disambiguation, and ultimately to the syntactic and semantic modules. PALAVRAS
was originally designed for written Brazilian Portuguese, but now recognises also
European Portuguese orthography and grammar, either directly (lexical additions) or
- if necessary - by systematic orthographic variation (pre-heuristics module).
Not all registers prove equally accessible to automatic analysis, thus phonetic
dialect spelling in fiction texts or phonetically precise transcription of speech data,
for instance, cause obvious problems. Scientific texts can have a very rich
vocabulary, but many of the difficult words are open to systematic Latin/Greek based
derivation, which has been implemented in PALAVRAS. News texts often contain
many names, but name candidate words can be identified quite effectively by
heuristic rules based on capitalisation, in combination with character inventory and
immediate context (cp. chapter 2.2.4.4). Only words derived from names (e.g.
adjectives) and chemical or pharmaceutical names evade this solution by not being
capitalised, and need to be treated by another morphological heuristics module, also
used for misspellings, foreign loan words and the few Portuguese words that are both
not listed in the PALAVRAS lexicon, and underivable for the analyser (cp. 2ii).
PALAVRA’s typical lexical recognition rate is 99.6-99.9% (cp. chapters
2.2.4.7 and 2.2.6). In these figures a word is counted as “recognised” if the correct
base form or derivation is among those offered (ambiguity is only resolved at a later
stage), and if propria are recognised as such (though without necessarily matching a
lexicon entry).
2.2 The program and its data-bases
2.2.1 Program specifications
7 Any orthographical changes introduced by the tagger's heuristics module - spelling/accent correction etc. - is marked
with an ALT-tag after the original word form. The xxx in (ii) means a hypothesized root not found in the current
PALAVRAS lexicon, or one normally disallowed by inflexional or word class - affix combination rules.
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