Inactive Tutor answered 05/30/19
Good Day!
The mirror talk technique is useful in developing confidence in oneself. It does not improve your language performance per se, however, belief in one's use of language has a significant effect on improving one's language performance over time.
Many people often fall behind in their performance of a language, mainly because they are restrained by their lack of confidence concerning said language. The speakers doubt in themselves is a big hurdle in learning a speech.
I hope this has helped you, and if you ever need help in anything else, just let me know!