Spoken and written French are so different that they can probably be considered two separate languages.
Nevertheless, most language courses and grammars ignore this issue and try to teach some sort of compromise language in which ‘money’ is argent, ne isn’t dropped, and the passé simple isn’t used.
“Street French” is one attempt at solving this, but it focuses too much on slang, and it still spells everything in normal French orthography.
Why hasn’t anybody created a language course and grammar of spoken French in which everything is given in IPA instead?
E.g., here’s the present tense of mɑ̃ʒe ‘to eat’:
A dialogue could look as follows:
ta d fʁik?
nɔ̃, ʒe pa d fʁik.
If only I was better at French, and if only I thought such a course would sell, I’d write it myself!