Eckhard Bick - VISL

1
Introduction
1.1 The ‘what’s, ‘why’s and ‘who’s
This dissertation is about whether and to what degree a computer program can be
made to handle the grammatical analysis of natural language, in the form of ordinary,
“running” text or linearly transcribed speech. The target language chosen is
Portuguese, and the basic method applied in the parser to be described here is
Constraint Grammar (first introduced in Karlsson, 1990), used in a context of
Progressive Level Parsing 1 . Along the way, I will be concerned with the interaction
between grammar system, parsing technique and corpus data, evaluating the trinity’s
mutual influence, and the performance of the system as a whole. In other words, in
computer linguistics, what can computers offer a linguist, and can linguistics inspire
computing?
Yet before trying to answer these questions with a 400-page bore of
technicalities and a load of secondary questions, it would seem relevant to balance
the introduction by asking quite another type of question: Why would any of this
inspire a person? Why would anybody want to court a computer for half a decade or
more? Well, personally - and may the esteemed reader please feel free to skip the
next half page or so -, I find that the most intriguing fact about computers is not their
data-crunching efficiency, nor their much-appraised multimedia capability, but the
plain fact that they react to stimuli in much the same half-predictable-halfunpredictable
way biological entities do. Computers communicate, and many a nerd
has found or created a social surrogate in his computer.
When I had my first naive date with a computer in 1973, the glorious glittering
consumer items of today weren’t called PC’s – or even Mac’s – but went by the
humble name of Wang. They had no hard disc, no floppies or CD-ROM’s, and 4 kB
of RAM rather than 40 MB. Yet, in a subtle way, human-computer relations were
superior to the uses most computers are put to today. Nowadays, most people treat
computers as tools: Gaming devices, mail boxes, type-writers, - all of which, in
different shapes, did exist before the advent of the computer. Then, children could
not shoot their way trough a boring day by handling fire-buttons, joy-sticks and
mouse-ears. They had to program their computer if they wanted it to play a game.
And the computer would respond, as a student surpassing her teacher, by route, at
1 Progressive Level Parsing is mirrored by the order of chapters in this book, which progresses from morphological
analysis and the lexicon to morphological disambiguation, syntax, semantics and applicational considerations. This is
why a discussion of the Constraint Grammar disambiguation formalism as such is “postponed” until chapters 3.5 and
3.6. Though I have tried to avoid literal CG rule quotes in the first chapters, there may be a few passages (notably 2.2.4
and 3.2-3) where readers not familiar with the basic notational conventions of CG might want to use later chapters for
reference.
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