Question: Does laughing break the salaah?
Answer: If on laughs so loud that he hears himself without the people around him hearing him, his salaat only, will break.
If he laughs so loud that the people around him hear him laugh, then his wudhu and salaat break.
If he smiles with no sound, his salaat nor wudhu break.
If one laughs in salaat, thinking low of the salaat, his Iemaan leaves him (He becomes murtadd).