Here's the meaning for those I recognize
LMAO (I think this is what you mean) - laughing my ass off
Ugh - English expression meaning 'yuck' 'awful' 'ick'
SMH - shaking my head
Xoxo - the x's represent kisses, the o's hugs, so kisses and hugs
Bae (I think this is what you mean) - slang term for a best friend, can also be boyfriend or girlfriend
Hmphf (or some variation of) - literally the written attempt to represent a 'sound' made for a response to something. Could indicate an agreement, disagreement or non-answer, depending on context.
D'oh (thinking this is a variation of duh) - an expression used to mean, 'gotcha/got you' 'of course' 'I see' but in the context of 'I should have known that'
I'm sure there are other interpretations, with broader contexts.
Hope this helps...from someone living in the US.
I sometimes refer to the 'urban dictionary' to look up things I don't recognize. It's good for slang definitions and cultural references.