你叫咩名啊
what's your name?

Cantonese Sentence Breakdown

你 nei5
you (informal, as opposed to courteous 您nín [您])
can be used to refer to an unspecified person
叫咩名 gou3 me1 meng2
what is it called
啊 haa4
modal particle ending sentence, showing affirmation
approval
surprise
appreciation
consent
request for an answer or confirmation