A person who speaks many languages is called a polyglot.

Additional Information:

• Polyglot : Someone who knows and is able to use several languages.
• Multilingual : Often used to describe a person who speaks multiple languages, though it can also refer to societies or documents.
• Hyperpolyglot : A person who speaks an exceptionally large number of languages, often more than six or seven.

If you're interested, I can also share tips on how to become a polyglot or famous polyglots throughout history!