Level A1
Yes/No Questions
A yes/no question usually starts with an auxiliary before the subject: do, does, did with an action verb; is, are, am, was, were with be; or words such as can, will, or have.
Do you speak English?
Look: Do you speak English? The helper do stands before you.
Forms
Do you speak English?— a normal action verb calls the helper do; with he, she, it it is does, about the past didIs she happy?— be calls no helper: it moves to the front itselfDid they go home?— about the past the helper is did, and the action verb stays plain: go, not went
A common mistake
Wrong: You speak English?
Right: Do you speak English?
So You speak English? is not a question yet. We say: Do you speak English?
More examples
Does your sister like music?
With your sister it is does: Does your sister like music?
Were you at home yesterday?
And with be in the past: Were you at home yesterday?