It's a polite way to ask someone their name. Here's a breakdown:
* 您 (nín): This is a respectful form of "you" and is used when addressing someone older or of higher status.
* 怎么 (zěnme): This means "how" or "what."
* 叫 (jiào): This means "to call" or "to be named."
* 什么 (shénme): This means "what."
* 呀 (ya): This is a sentence particle used for emphasis or to soften a request.
Putting it all together: 您怎么叫什么呀 (Nín zěnme jiào shénme ya) literally translates to "How do you call what ya" and is a more polite way of asking "What's your name?"
However, in everyday conversations, it's perfectly acceptable to use the shortened form: 你叫什么? (Nǐ jiào shénme?) which means "What's your name?" and is less formal.