mother tongue

Meaning

Noun

• The language one first learned; the language one grew up with; one's native language.
• The language spoken by one’s ancestors.
• The language spoken by one's mother, when it differs from that spoken by one's father.
• Informal speech, as opposed to educated language.

Origin

• From Middle English mother tonge, modyr tong, equivalent to . Compare Old Norse móðurtunga.