Polyglotism or polyglottism is the ability to master numerous languages. Multilingualism is a word with a similar meaning.
Richard Hudson, professor emeritus of linguistics at University College London, coined the term "hyperpolyglot" for a person who can speak twelve or more languages fluently.
There are many theories to explain the existence of polyglotism in some individuals, including differences in intellect and brain structure.
It is difficult to judge which individuals are polyglots, as there is no uncontroversial definition of what it means to "master" a language. Nonetheless, many people have been described as polyglots. This includes some cases of "polyglot savants", people who show mental disability in some areas but unusually high ability to learn or use languages.