Learn English – say: You are out of the mind

You speak no English (= “You don’t speak any English”) means, literally, “You have no ability to speak English” rather than “You don’t speak any kind or dialect of English”.

In the context of the song, however, You speak no English is a metaphor (or, arguably, a synechdoche) for “You are ignorant and inarticulate”—specifically, “You have no artistic sensibility”.

Four niggas in a whip
All foes say they ain’t fucking with Trice shit
Somebody’s lying, I’m undenying, denying me means that
The driver got influence over you on certain things
Be distinguished, just cuz you ain’t feeling his favorite emcee
Don’t mean you speak no English
Hop out the car, catch the bus
At least you be established as the man that you are

Obie Trice invites his listeners to assert their own musical preferences and renounce the ‘influence’ of those who have achieved material success (a whip is a Mercedes or similar expensive, high-status car) when they sneer at Obie’s music.

Just because you’re unimpressed by their favorite artists doesn’t mean that you have no musical taste.

Twin brothers refers to two people. A couple of twin brothers also refers to two brothers; the word twin functions as an adjective modifying brothers and has no effect on the number of people in the group.

If there were five people in the group, you might say:

A mom and a couple of sets of twin brothers.

Or, if only two of the five were twins:

A mom and four brothers, two of which are twins.