There are several prefixes in the Hebrew language which are appended to regular words to introduce a new meaning. In Hebrew, the letters that form those prefixes are called "formative letters" (Hebrew: אוֹתִיּוֹת הַשִּׁמּוּשׁ, Otiyot HaShimush). Eleven of the twenty-two letters of the Hebrew alphabet are considered Otiyot HaShimush. These letters are Aleph (א), Bet (ב), He (ה), Vav (ו), Yud (י), Kaf (כ), Lamed (ל), Mem (מ), Nun (נ), Shin (ש), and Tav (ת). A mnemonic to remember these letters is איתן משה וכלב (Eitan, Moshe, v'Kalev), which translates to "Ethan, Moses, and Caleb."