Definition of polyglossia in US English:

polyglossia

noun

Linguistics
  • The coexistence of two or more languages, or distinct varieties of the same language, within a speech community.

Origin

1970s; earliest use found in International Migration Review. From poly- + -glossia, after diglossia.

Pronunciation

polyglossia

/ˌpɒlɪˈɡlɒsɪə/