A similar lesson served me well when learning German while living there. My German pronunciation (and some grammar) improved in lock step with my ability to mimic a thick German accent in English.
Being able to systematically reproduce typical German “errors” in English taught me how to speak correctly when I switched to pronouncing German words.
Yeah: that is a brilliant technique that (1) encourages you to learn to not be embarrassed to use the correct sounds, and (2) really helps others understand what you are saying (especially if you have a strong local accent like me as a kiwi).
In Spanish, I also tried to use words with Latin roots, and avoid words from other languages. Often pure guesswork, or even making up words by changing endings, but sometimes worked surprisingly well if you know a little etymology and have learnt a little feel for the grammatical rules. Then again, made some doozy mistakes too - mostly hilarious or surreal!
Being able to systematically reproduce typical German “errors” in English taught me how to speak correctly when I switched to pronouncing German words.