The use of or knowledge of two languages, or the practice of writing or publishing in two languages.
Derived from Greek 'di-' (two) and 'glotta' (tongue), plus the suffix '-ism'. It developed as scholars and printers needed a word to describe the phenomenon of bilingual composition.
Medieval monks practiced diglottism constantly, creating Latin-Old English glosses in manuscripts—they were basically the first language learning apps!
Complete word intelligence in one call. Free tier — 50 lookups/day.