I want to apologize first of all for having the wrong publisher for An Introduction to Functional Grammar.   It's Edward Arnold (1994).  Oxford is the publisher of Spoken and Written Language (1989), which is indeed the test on spoken language I referred to.  My computer is at work and my books are at home, and I shouldn't rely on memory.

     I don't want to get too caught up in turf wars.  I would, if anything, like to be a synthesizer and a healer.  What I find most immediately usable out of Halliday is the notion of subject functions (actor etc., grammatical subject, and theme), and the attempt at least to map out representational meanings beyond the very clumsy division into subject and direct object that traditional grammar has given us.  The boy kicking the ball is much, much different from the man admiring Ghandi, and Ghandi and the ball are affected in remarkably different ways.  I want to say also as a writer and a writing teacher, that I am at work in the making of meanings and at work in helping other people make meaning making decisions.  Whether or not Halliday is able to account for all forms as functionally driven is absolutely irrelevant in that day to day task. A doctor and a research biologist have different problems to solve, and mine is much closer to the doctors.  The deep problem in using his work in a practical grammar text in the U.S. is that the terms are so foreign to those front line teachers who will be using the text and the students exposed to them will go on to other courses and have no one to talk to. (Though my students who have gone on to do grammatical analysis in English classes have baffled their teachers, but impressed them as well.  It conveys an interesting power.) Since reading Halliday, I find it useful to think of all verbs as processes and all verbs as carrying their own transitivity.  Mental process is a rough category, but a highly useful one. (Itself broken down into sensing, feeling, and thinking.)  If categories get fuzzy at the boundaries, that does not diminish their usefulness so much as affirm, once again, that language is larger than our attempts to understand and explain it.
     Let me say it this way, and not at all as an attempt to knock what anyone is doing in this marvelous enterprise.  A purely descriptive or purely formal grammar, as important as that may be in the grand intellectual scheme of things, will not and cannot solve the problem of what to teach our kids.  For all the problems of traditional grammar, it does attempt to be functional, and we will not be able to replace it until we can  do so with a more functional alternative.