How important is the knowledge of grammar in spoken English? The importance of learning grammar can hardly be overemphasized especially keeping in mind that it is not our mother tongue. And the grammar is the mother of any language. But the the most surprising fact remains all the traditional grammar books have a bias towards written English. We do not have any grammar book dealing with some distinctive features of spoken English. It must be remembered in this context that we speak the language face to face and it is not preplanned and takes place real time in an interpersonal and social situation. Unlike written English where you have the freedom of choice in writing a letter or e-mail or an article or advancing an argument.
In written English sentences begin with a capital letter an have at least one main clause but it is not so easily identifiable in the case of spoken English. Primacy of expressions rules order of sentences which are characterized by use of interjections, just a single word, phrases and incomplete sentences with pauses and modulation of voice and proper intonation. Another aspect in spoken English is accent on syllables which is absolutely essential to learn pronunciation correctly. Traditional grammars are generally not of much help. Grammar at advanced levels do contain contents on this which do not cover enough distance from the spoken English point of view.
Another noteworthy feature of spoken English is there is no order in speaking turns. In a typical an casual conversation one speaker face interruption from another, topics ranging stock market, current politics, day's weather etc., to wife's illness , daughter's birth day and what not!
All their opinions, anger, frustration, annoyance, joy are expressed in irregular forms, out of contexts through liberal sprinkling of exclamatory words, ellipsis and idioms which are relevant in spoken English. There arises the need for a grammar to cater to the needs peculiar to spoken English.