Remember that to speak was говорить, and I speak thus became говорю.
We had the у in хочу change to шь in хошешь. We can apply a very similar rule to говорю and have ю change to шь to get from the I to the informal you form.
Russian for you speak is говоришь.
Russian for what about is simply А.
This word А is actually called the contrasting and. It can have the sense of what about. It could also have the sentence of talking about ... or simply and. You use this word when you want to change the subject a bit. You can also you use when you want to contrast with what you talked about (for example, in phrases like I am from Russia, where are you from? - not expecting that the other person will be from Russia too).
Here's an example of how it is used:
I speak Russian. What about you? would be Я говорю по-русски. А ты?
I am from England. And you? would be Я из Англии. А ты?