However, we do need to be aware of how much we ourselves are speaking. If we talk all the time, however comprehensible our language is, the students are denied their own chance to practise production, or get exposure through other means (from reading or listening to tapes, for example).They may also become bored by listening to the teacher all the time.
Basing a lesson on what we can do ourselves as in the examples above clearly has the enormous advantage of not being susceptible to technical malfunction (though that can happen!), power cuts, or unavailability. However, an over-reliance on what we ourselves can offer places excessive demands upon us. It is hard to be permanently motivating and amusing, and it is taxing to have to offer a perpetually varied diet of voices, gestures, and expressions. Nevertheless the ways in which we use our voice, the ways in which we model language and employ gesture and expression are all basic and important teaching skills.