prata = talk tala = speak "tala" in Swedish is not as common as "speak" is in English. I myself almost never use "tala" except for some constructions, for example "modersmålstalare" (mother tongue speaker / native speaker).

The first one means can you talk English, like have a conservation with someone. But the second one means can you speak English, like maybe pronounce English words. But it doesn't nesseraly mean you can understand English. It makes a whole lot easier to just ask them, kan du prata engelska? Hope that helps you. Good luck learning Swedish, it's has a lot of simplerates to english.