A multilingual person or polyglot is the name for a person with a high degree of proficiency in several languages.

The world greatest living polyglot is Ziad Fazah (born 1954) who apart from his mother tongue Arabic is reported to speak 55 other languages. Calculations as to how many languages now-dead polyglots spoke is difficult, since no one can offer a objective description of what is required to "know a language" fluently, but the greatest linguist in history is believed to be cardinal Giuseppe Gaspardo Mezzofanti (1774-1849), who is reported to have spoken up to a hundred languages fluently. On a visit from the Lord Byron, he surprised Byron by showing a more extensive knowledge of local London slang than the poet himself.

Noted polyglots (12 or more languages):

Note: a bilingual person can speak two languages fluently, a trilingual three.