I heard "Han skrattar fult". Would that be the same pronuncation if spoken fast, and would that be proper Swedish?
They're certainly close! But it's not the exact same. I'm confident most natives would hear the difference virtually every single time.
I heard exactly the same. The only difference in pronunciation seems to be the ä in är. Luckily in this sentence it does not really change the meaning of the sentence. I think it usually is clear from the context.
I was listening recently to someone describing working with the late actress, Mary Tamm, that while she had a serene face she also had the dirtiest laugh
Have a listen to some of the examples here and it might inspire you :) https://www.ted.com/talks/sophie_scott_why_we_laugh?language=en
I much agree with MarksAaron, and think that "laugh" should be the preferred noun.
"U" in "fult" ends with some labial sound like a little, hidden "b", right?