Yiddish

Yiddish is a language derived from German but written in the Hebrew alphabet. It is spoken by Jewish people all over the world. It literally translates as "Jewish" and.

Being Jews, Howard and Mrs. Wolowitz occasionly use Yiddish words in conversation, such as "shiksa" (non-Jewish woman), "kreplach" (filled dumplings), "ferkarkta" and "putz". While Raj seems to know some words as well (such as "kreplach"), Sheldon does not (0207, 0302).

In the beginning of The Panty Pinata Polarization, when the guys play Klingon Boggle, Howard tries to mix the Yiddish word "kreplach" into Klingon words, but is seen through by Raj:

Raj: Hold on a second. Kreplach?? Howard: Yeah. Raj: That isn't Klingon. It's yiddish for meat-filled dumpling!

In The Jiminy Conjecture (S3E02):

Raj: What happened? Sheldon: Obviously another carnal fiasco with the 'Shiksee' goddess. Howard: Shiksa. Shik-Sa. Sheldon: Forgive me. Yiddish was not spoken in East Texas. And if it was, it wasn't spoken for long.