Birthtongue

In replying timidly, Anita revealed her foreign accent, which was instantly observed. “You are American, of course? No? English? Ah, how stupid I am!" Forthwith he began to talk fluently in German, though Anita saw it was not his birthtongue.

And now I place them, palms up, wrong five-legged beasts with their underbellies exposed, on the desk for you who have told me, in your own broken wedding of English and your birthtongue, […]

"No problem. Neo-Gaesh, and that's Orlen's birthtongue."

Faan talked constantly to herself and to anyone who'd listen, mixing the Fadogur she was learning with her birthtongue in a hash of sound that gradually grew more comprehensible.

Other forms of cultural non-homogeneity (birthtongue or ethnic identity, for example) have, in the generally supportive nature of the group process, tended to become not only not a problem, […]

When this warning failed to cure the boys of recklessness, he made them recite the first apothegm of Tholjassan battle-dance at the start of every lesson — not just in Arquali, but also in their individual birthtongues: […]