A drill is a classroom technique used to practise new language. It involves the teacher modelling a word or a sentence and the learners repeating it. There are different kinds of drilling, such as choral drill, which involves the whole class, and substitution drill, where the teacher changes the cue words after each repetition.

The following sequence is an example of a substitution drill
Teacher: I like cheese
Learners: I like it
Teacher: I like apples
Learners: I like them
Teacher: I like Sue etc

In the classroom
Drilling is a classroom technique which some teachers reject due to a possible lack of communicative quality and its highly controlled, teacher-centred nature. However, there are advantages to it also, such as offering learners an opportunity to practise pronunciation in a non-threatening dynamic.