Xenophone

From xeno-, from Ancient Greek ξένος (xénos, “foreign, of a stranger”) and -phone φωνή (phōnḗ, “sound”), that is, “foreign sound.” A speech sound used in a language (L1) that is not part of the phoneme (or allophone) repertory of L1 but is borrowed from another language (L2, L3, Ln) when pronouncing words and names from that other language. An example from Swedish is the voiceless dental fricative (θ) in the name Thatcher, which is used by most Swedes in everyday conversation (in Swedish, talking to other Swedes) but is a speech sound that does not (any longer) belong to the Swedish phoneme set.