Comparing English with Vietnamese, Vietnamese is much simpler than English when it comes to questions. Most of the questions in Vietnamese expect a yes/no answer.
(lit. Person – this – have – old – or – not)
Is this person old?
The affirmative answer is (co = have/yes) and the negative (khong = no). There is no inversion in Vietnamese language (Is this ...?). As you can see in the above example, the commonest question form in Vietnamese, expecting a yes/no answer, offers the choice of an answer by inserting the word (co = have) before the verb or adjective and the word (khong = no) at the end of the question.
The negative word in Vietnamese precedes the verb or adjective as is shown in the following example.
(lit. Person – this – not – old.)
This person is not old.
In most cases, Vietnamese speakers of English omit the auxiliary verb (especially the verb “to be”). This problem persists and it is very difficult to fix.