Your mother tongue is the first language you grew up speaking. Speak in her mother tongue, a mother tongue speaker, lose the mother tongue.
Losing it is common in migrant families by the third generation, and keeping it takes deliberate work. Norse had the same compound, which suggests the idea is very old indeed.
1phrasemother tongueThe first language you grew up speaking.
“Her mother tongue is Welsh, but she speaks English at work.”
mother tongue is a language.
Also accepted in games: native language
Middle English mother tonge is mother plus tongue, and Old Norse had the same compound.
Middle English
mother tonge
English, today
mother tongue
From Middle English mother tonge, modyr tong, equivalent to mother + tongue. Compare Old Norse móðurtunga (“mother tongue”).
Etymology from Wiktionary, CC BY-SA
Practised in News & Communication