What's the difference between "speak" and "talk"?

Hi,

Could anybody please tell me the difference between the sentences: a) "I'm talking.", and b) "I'm speaking."?

Thanks in advance.
Minhaz

In a lot of cases both words can be used but for me "talk" tends to suggest a 2 way conversation more then speaking. For example we talk about "speaking in public" not "talking in public".

*Not a teacher

They may be similar or they may be different.

Similar: Eg Paul spoke to Fred yesterday; Paul talked to Fred yesterday. In both cases, Paul had a word with Fred, no more related. That's clear.

Different:
=> Eg Paul can speak English; Paul can talk English. Here, speak implies a capacity, a can-do in a specific language while talk does not.

=> Eg Paul is speaking about the weather; Paul is talking about the weather. In that case, we do not care about the capacity of speaking a language. The matter is the weather, the discussion about the weather. So Paul is talking about English would be fine.