To monitor is to watch and listen to learners while they are doing an activity but not to lead them in the activity. Teachers monitor to find out what problems the learners are having, and to identify the type of errors learners make as they produce language.
The class break into pairs to practise pronunciation of contracted forms in a short dialogue. The teacher walks around the class monitoring for difficulties and corrects where necessary, then talks to the whole class about common mistakes.
In the classroom
Monitoring is an important classroom technique and works best when it is directed at lesson aims. Teachers can take time to explain to learners why they are doing it, and negotiate when they will give feedback on problems.