Eckhard Bick - VISL

information is (a) of the same notational type and (b) string coded rather than structure
coded. Tag notation combines both advantages - information from all levels can be
lumped together as "words" in a string. Constituent analysis, in contrast, involves either
graphical computation tools or at least bracket matching algorithms, both of which are
more complex than the ordinary search-and-replace tools needed for manipulating tag
strings.
As mentioned, structural incompatibility (1e-f) is harder to handle than mere
category distinctions, for a variety of reasons. One of the reasons is, that a change from
one structural notation to another may force a theory/notation-inherent distinction, that
is left under-specified in the other system. In these cases, no equivalent notation exists,
all transformation is mandatorily "upward", like hierarchical PP-attachment when
moving from traditional CG grammar to PSG tree-structures, or head-dependent
distinction (1f) when moving the other way.
In tag notation, function cannot be expressed other than explicitly, and
dependency relations are a minimal way of doing this. Higher level function tags, like
subject, object and the like, make things even worse, since they are often only implicitly
marked in constituent analyses, as when defining an (English) subject as a clauseminus-VP-constituent.
Moving from function-tag to constituent-tree is, by comparison,
relatively "easy" (cp. 4.6.3) - though still considerably more demanding than
Portmanteau-fusing or level-movement (1a-c). This asymmetry in transformability is yet
another argument for making (word based) tagging the primary notation.
The 1:1 transformation of pronoun subclasses in table (2) can serve as an example
for a theory dependent tag filter. In my system, there are three pronoun classes, all
morphologically defined: Personal pronouns (PERS), determiner pronouns (DET) and
specifier pronouns (SPEC). Functionally, all can substitute for whole NPs in the role of
subject, object etc., but only DET pronouns can appear as adnominal modifiers (@>N).
The three classes correspond in traditional Portuguese grammars to 6 "pseudosemantic"
pronoun classes 213 and the "functional" article class:
(2) Table: pronoun subclass filtering
Traditional pronoun class CG tags
personal pronoun PERS
possessive pronoun DET
demonstrative pronoun DET/SPEC
interrogative pronoun DET/SPEC
relative pronoun DET/SPEC/ADV @#FS/AS-N<
indefinite pronoun DET
213 Sometimes the category of reflexive pronoun is added, which would have to be filtered as a syntactic subclass of personal
pronouns: PERS.
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