What are the strengths and weaknesses of the inter language theory?

Some of the strengths of inter-language theory are that it is systematic and universal by nature. It has liberated language teaching methods and paved the way for a communicative teaching approach. Some of the weakness of the inter-language theory are that it is extremely criticized for it's limited explanatory powers. It is based on fault learning, which can lead to a lack of motivation, especially if criticism is not constructive. The theory cannot place an exact emphasis on correct interpretation between the speaker and the listener.