At a store, I heard one employee ask another the equivalent of this in French:
Does he have his card?
Can you guess how the employee might’ve said it? She said it in an informal way, without using est-ce que.
Here’s what the employee said:
Y’a-tu sa carte?
In this question, y’a-tu means does he have?, has he got?
Il a sa carte means he has his card. But, in colloquial language, it’s more likely to be pronounced y’a sa carte. (This is because the final L sound of il is very frequently not pronounced: i’ a sa carte.) Then, by putting tu after the verb, we turn y’a sa carte into an informally asked yes-no question: y’a-tu sa carte? (Remember, this tu doesn’t mean you.)
In other questions, y’a-tu can mean is there?, are there?
Y’a-tu un problème?
Is there a problem?
This time, though, y’a is an informal pronunciation of il y a, not il a. This informal pronunciation occurs because the il of il y a is losing its L sound again: i’ y a. Then, by putting tu after the verb again, we create an informally asked yes-no question: y’a-tu?, is there?, are there?