Could be a Cantonese word with multiple meanings, one can distinguish which "hai" the speaker is referring to by the tone(Cantonese is a tonal language), which is very difficult to explain in words.
1. Yes/is , to affirm, written as 係
2. In/on/at, to specify location, written as 喺
3. Cunt, extreme offensive term for vagina, written as 閪