3 Quotes by I.S.P. Nation

Teaching a particular word can only be one step in the gradual learning of that word, so we should not spend too much time on it. The main opportunities for vocabulary teaching should be during intensive reading and when learners ask for words during speaking and writing activities.

Adding an extensive reading program to a language course is the most important improvement that a teacher can make, and if this was the only improvement made, the teacher could still feel very satisfied about that.

There is another reason for not spending too much time on complex grammatical features. It is not easy to explain the meaning and function of these features. If it is difficult for teachers and grammarians to understand the meaning of these features, it is going to be even more difficult for learners of the language. These features are best learnt through experience, through meeting them many times in input and through having to use them in output.