Question: what is a tilde used for?
Answer: In phonetics, a tilde is used as a diacritic that is placed above a letter, below it or superimposed onto the middle of it: A tilde above a letter indicates nasalization, e.g. [ã], [ṽ]. A tilde superimposed onto the middle of a letter indicates velarization or pharyngealization, e.g. [ɫ], [z̴].