"How many languages do you know?"

I regularly get asked: "How many languages do you know?"

The question confuses me. What does the person mean by it? If I ask them to explain, they may continue:

"How many languages do you speak?"
"Are you fluent?"
"Do you sound like a native speaker?"

Which doesn't really help, as none of those questions means the same thing.

Let me say something contentious here. It's that I don't believe it is possible to master any language as well as your own. I don't think that you ever get to that point.The reason being, you cannot possibly put in the hours.

I read once that by the time an average schoolchild gets to high school age, he or she has been exposed to about 12,000 hours of French.

Well, good luck with matching that at the rate of an hour of two of study per day.