Noun
A separate language for expressing ideas, as opposed to the vernacular (mother tongue) which is employed for everyday speech.
Antonym: mother tongue
The form of language acquired through education and reading, as opposed to the dialect one grows up speaking; educated or formal language.
Antonym: mother tongue
A second language that one speaks fluently.
The language spoken by one's father, when it differs from that spoken by one's mother.
Antonym: mother tongue