In English, "I swim." (but not "I am swimming.") can also mean that one is able to swim or knows how to swim. Can we do this in Dutch?
No, I don't think so. 'Ik zwem' only means the action, so 'I am swimming'. If you want to tell someone that you I know how to swim, it would be 'Ik kan zwemmen' or 'Ik weet hoe ik moet zwemmen'.
I know ''w'' sound like ''uh'', is that true..?
Don't think so? It does sound different than the English 'w'.
'Zwemmen' is pronounced like this.
The Dutch w is between the English w and v.