The study of linguistics has been forever changed by the advent of the
computer. Not only does the machine permit the processing of enormous
quantities of text- thereby securing a better empirical foundation for
conclusions-but also, since it is a modelling device, the machine allows
the implementation of theories of grammar and other kinds of language
processing. Models can have very unexpected properties- both good and
bad-and it is only through extensive tests that the value of a model can
be properly assessed. The computer revolution has been going on for many
years, and its importance for linguistics was recognized early on, but
the more recent spread of personal workstations has made it a reality
that can no longer be ignored by anyone in the subject. The present
essay, in particular, could never have been written without the aid of
the computer. I know personally from conversations and consultations
with the author over many months how the book has changed. If he did not
have at his command a powerful typesetting program, he would not have
been able to see how his writing looked and exactly how it had to be
revised and amplified. Even more significant for the evolution of the
linguistic theory is the easy testing of examples made possible by the
implementation of the parser and the computer-held lexicon. Indeed, the
rule set and lexicon grew substantially after the successes of the early
implementations created the desire to incorporate more linguistic
phenomena.