Once language is internalised, it can then be retained and retrieved when needed for communication.
Example
A learner finds that using a spidergram helps them record a new lexical set on words that describe emotions effectively and so internalising this new vocabulary is easier.
In the classroom
A learner discovering for themselves what the meaning of a new word is by using context will internalise this information more deeply than a learner being told what the meaning is. This kind of processing is key to techniques such as guided discovery, learning strategies such as the example above, and task-based learning.
Further links:
https://www.teachingenglish.org.uk/article/drilling-1
https://www.teachingenglish.org.uk/article/make-no-mistake
https://www.teachingenglish.org.uk/article/core-activities-using-chart-integrate-pronunciation
https://www.teachingenglish.org.uk/article/lexical-approach-2-what-does-lexical-approach-look