As a teacher-trainer, I have been accused of being pedantic when I refuse to accept such written forms as: I think John should of done it; I have been accused of lowering standards when I have said that trainees should teach their students to utter the words I think he should have as /eI θIŋk iː ʃʊd əv/; And I have been called a hypocrite when both things have occurred in the same session.
What many people, including some teachers, unfortunately, do not realise is that written English and spoken English are two different things.
If we are describing our thoughts about a certain person’s unfulfilled obligation in writing, then the written form accepted as correct at present throughout the English speaking world is either I think that he should have done it or I think he should have done it. Fifty years ago my schoolmasters insisted on the that in ‘correct’ written English, but most of us do not insist on that now. The fact that the letter h appears at the beginning of the words he and have does not mean that they necessarily need to be pronounced in the normal conversation, though they may be pronounced in formal rhetoric. It is not ‘uneducated’ to drop one’s aitches after consonant sounds in conversation; most speakers, even professors of English, do it. The natural form of the utterance of those words for southern British speakers is: as /eI θIŋk iː ʃʊd əv dʌn It/. This may be rendered in informal writing as I think he should’ve done it.
Unfortunately, the /əv/ pronunciation of the word have is identical to the pronunciation of the weak form of of. This is what causes uneducated people to write ‘should of’. This is as incorrect as the ate rendering of 8. In fiction, writers may indicate their desire to present a character in a certain way by having the character say should of. This indicates to the reader that the character is uneducated. (Even though the pronunciation of educated and uneducated people is actually the same here!) We have a similar situation when a writer will indicate that a character says sez; the pronunciation, /sez/, is exactly the same of that of an educated person, but the latter’s utterance would be spelt s a y s.
So, insisting on the correct form in formal writing is not pedantry; and dropping your aitches and using contractions in speech is not lowering your standards. It is accepting the realities of the language.