In several American movies you've heard expressions like "she don't know" or "she don't like.."
The context is quite familiar or informal, english has many different registers. The way way English is actually used in real life isn't the manner described by most grammar books.
AND this particular dialect of English that's being discussed here is called "African-American vernacular English" , also called black or AAVE in common language.
It's believed that AAVE has grammatical origins in, And pronunciational characteristics in common with various West African languages.
*she talkin (she is talking).
*I go, they go, he go (=he goes, in standard English), she go (=she goes).