Tip: If you have a list of functional phrases on the page, or a short dialogue, get your students to speak the phrases aloud to themselves in a low voice. It’s an individual activity so they should all start at a different place/time to avoid a class chorus.
I’m always looking for ways to help students to increase their depth of processing of lexis. Here is a really simple idea. You start with any list of functional phrases (eg from a coursebook) and just ask the students to say the phrases to themselves in a low voice, several times. It’s like self-drilling. I do this after the coursebook activity that presents the phrases, and before the activity where they are meant to be used. It increases the chance that they actually will be used.
With listening material I might use the same idea with the audio script, after the listening task is finished. I ask students to look at the script and then read a short, lexically rich section aloud to themselves in a low voice several times. They read all the parts themselves (it’s a personal, individual activity, not dialogue practice with a partner).
In all cases I go round the class and monitor, helping the students to pronounce correctly and stress correctly.
Note this classroom management point: it’s very easy for all the students to say the same phrases at the same time. You don’t want this. Students should be in their own interior world, repeating again and again as they wish, not listening to other students.