did teach/taught ?

[ph2004]

Is "Who did teach you that ?" correct ? Or should one only say : "Who taught you that ?"

[bhaisahab]

Is "Who did teach you that ?" correct ? Or should one only say : "Who taught you that ?"

"Who taught you that?" is the correct form.

[philo2009]

Is "Who did teach you that ?" correct ? Or should one only say : "Who taught you that ?"

Both are perfectly possible, but the first is highly emphatic, and would occur only in an exchange such as

A: Did your father teach you that?
B: No.
A: Did your mother teach you that?
B: No.
A: So, who did teach you that?

For normal, non-emphatic use, the second is standard.

[konungursvia]

Rough winds do shake the darling buds of may.