Difference between multilinguists and polyglots

A multilinguist is one who speaks or knows many languages.

A polyglot is one who speaks or knows many languages

What is the difference between a multilingual , multlinguist and a polyglot? can we call all multilinguals polyglots?

Here are the two links.

https://www.collinsdictionary.com/dictionary/english/multilinguist

https://www.merriam-webster.com/dictionary/polyglot

Solution 1:

The Google ngram viewer shows that multilingual only appeared about 1940 and has gradually overtaken the older polyglot.

I suspect that because the latinate word was more closely related to English words, it was more acceptable to the post-war generation from non-upper class backgrounds that was receiving higher education for the first time. As well as perhaps not knowing what glot meant (lacking Greek, like me) they probably felt it sounded somewhat unpleasant — an aural association with glob and clot.

Solution 2:

Latin multi = Greek poly = English many

Latin lingua = Greek glotta = English tongue

The difference in English usage is that "multilingual" is an adjective, while "polyglot" can be an adjective, but more commonly it is a noun.