I am not a linguistics graduate, but I think audiolingualism is drilling patterns, and then adapting the pattern. This is a pen, those are pens; this is a chair, those are chairs; this is a? Those are ?
The text isn’t clear. I don’t see how the theory of a language is clear. I have tried to summarise it:
Richards says AL is the most popular language teaching method. It is based on two theories:
- of language: structural linguistics
- of learning: behaviourism
The quote said that teaching relied heavily on behaviourism. Teaching was based on repetition of dialogues and patterns to make them automatic. Then they transferred the patterns they had learned to new patterns.
Even though the theory of behaviourism is mostly discredited ( this is news to me) some aspects such as drilling are still popular today.
He uses some drills when he himself is learning and teaching. However, I don’t know what he means by communicative cast.
There was a lot of criticism of AL, structural linguistics etc in the 1970s. There was coincidentally a rise in new methods such Silent Way and Suggestopedia, which in 1991 he called designer method, (probably so you can go and buy his book)...
Hope this helps. Good luck.