In Vietnamese, we use à (as well as hả) to form presumptive yes-no questions.
Presumptive yes-no questions are yes-no questions with a presumption. They are used to seek confirmation of something the speaker presumes to be true. Note that using presumptive yes-no questions implies that there is a presumption.
For example, if you hear someone speaking Vietnamese, then the question “Are you from Vietnam?” is used to seek confirmation of whether that person is from Vietnam. That is an example of a situation where you would use a presumptive yes-no question because the fact that he speaks Vietnamese leads to you presuming that he is from Vietnam. If there are no presumptions (no reasonable clues leading to), you can’t use presumptive yes-no questions, but rather use normal/neutral yes-no questions.
Structure
Add à to the end of a statement to form a presumptive yes-no question.
Statement + à?
An alternative to à is hả (same meaning), which is widely used in the Southern dialect.
Statement + hả?
When asking questions like this, the speaker presumes that the statement is true and seeks confirmation from the listener.
Examples
The examples below are translate into English as tag questions. It’s not really the same concept, but it’s the best we can do. The reason is that the questions rely on the semantics and pragmatics of the particle à, which doesn’t have an equivalent in English (as is the case with every other Vietnamese particle).
- Hôm nay anh không đến à?
Today you aren’t coming, are you? - Cô ấy biết bơi à?
She can swim, can’t she? - Anh cũng là lập trình viên à?
You are also a developer, aren’t you?