A person with two languages is bilingual. A person with three or more is multilingual. Looking for a word that describes the exact number of languages would seem disingenuous.
You would be called a quadrilingual.
A person who speaks four languages is called a quadrilingual.
People who speak several different languages are called polyglots.
Being able to speak two languages is called bilingualism.
four
A person who can speak two languages is called a bilingual.
Someone who can speak two languages is called bilingual.
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multilinguist, polyglot; use dictionary.com for more reference
A person who can speak different languages is called a polyglot.
Being able to speak two languages is called being bilingual.
Multilingualism.