A foreign language is not forgotten over time.

Even 50 years after learning a foreign language, the level of proficiency in it remains the same. These conclusions were made by scientists from the University of York. They rounded up 500 Britons who had taken A-levels in French from 1970-2020 and gave them a second test. Volunteers from the older group did just as well as recent graduates. People remember words the same way they remember facts, dates, and names. Over time, they may begin to be forgotten, but grammar is learned once and for all - like riding a bicycle.