I've always found David Crystal's work illuminating, and have just caught up with his autobiography, published in 2009. I was pleased to see the short shrift he gave to Chomsky and the principle of his Language Assessment Remediation and Screening Procedure, which is to consider the person in front of you and what their needs are. The acronym LARSP is another matter - I still have trouble remembering what it means.
However, a case he cites, of moving a child from a two-word construction - man jump ; see car; red ball - to three, is an interesting demonstration of the relative importance of different parts of speech. Each of these fragments contains a noun, and two out of three a verb. I infer that noun and verb are the main building blocks of language, and other parts subordinate to them. I call them "companion words", adding to the sense of noun (adjective) and verb (adverb), saving time (pronouns) or holding things together (articles/determiners and conjunctions, which I call links). The approach is very similar to what Chomsky called "teaching transformational grammar", an activity he condemned. However, Chomsky is not a teacher, and is wrong once again.
There is a similar insight into the issue of time and tense with verbs. For European linguists, the terms are synonymous. English-speaking linguists reserve the term tense for a change in the form of the verb, and Professor Crystal has used the term "aspect" for other ways of indicating time, such as "He goes to university next week. He is off to university next week. etc." However, in this book he notes the influence of what linguists call "adverbials" - why not just adverbs, with the understanding that they can comprise more than one word - in providing the signpost of time. He may well have made the same point elsewhere and I've missed it, but this time it came across very clearly.
We indicate time in English either by a change in verb form, or by context, usually an adverb. "Once upon a time," indicates that something has already happened, and cannot be followed by a present or future verb, any more than "Tomorrow" can be followed by a past one. I call a compound verb, such as I will go a change in form. Ich werde in die Schule gehen is in the future tense in German, just as I will go to school is in English. The term time zone is, as I've argued elsewhere, more useful for teaching purposes than tense, a word that means nothing to anyone who does not have a working knowledge of French etymology.
David Crystal's book reflects much of the history of modern linguistics, with generous and well-merited account of the work of Randolph Quirk, and of modern family and academic life. There are ups and downs, and a shining example of courage, when he left Reading University without a redundancy package to move to the life of an independent scholar in Wales, with a radio studio built into his house. His invaluable Cambridge Encyclopaedias, respectively of Language and English, rescued his finances, and he became an editor of general encyclopaedias, using the experience of classification this provided as a basis for later work in search engine design. His latest (or so I thought...) books on spelling, grammar and punctuation , published after the autobiography, are to me the most valuable, and provide, with Harry Evans' Essential English, an excellent basis for understanding how our current language has developed and works.
Professor Crystal dislikes linguistic purists, and yet, like all others who do so, writes in immaculate standard English throughout. Language changes slowly, and there is no discernable difference between his grammar and that of Dickens and Lewis Carroll. Food for thought throughout, and recommended.