"Dieuh neh lio moh sai-loh" is a Cantonese phrase and is a very derogatory statement.
Considering that someone might have used that phrase at you and you want to know the meaning - it is very inappropriate and refers to the other person's mother.
If you are a teenager or child, please report it to someone older whom you trust. Do not indulge in verbal fight with the person who said it to you.
"Dieuh neh lio moh sai-loh" in Chinese translates to "你好吗?" in English, which means "How are you?"