When 2 languages exist in a community, one used a lot and the other used less. The more used language is formal and the other is a colloquial type.

DIGLOSSIA: "Diglossia occurs where 2 forms of language are used in a community."
Cite this page: N., Pam M.S., "DIGLOSSIA," in PsychologyDictionary.org, April 7, 2013, https://psychologydictionary.org/diglossia/ (accessed January 17, 2021).