The Greek and Hebrew that is translated as “leaven” (or “yeast”) in English is translated in Tzotzil as “the thing that swells the stomach of bread” and in Mairasi “bread cooking ingredient” (source: Enggavoter 2004)
In the occurrences in Mark 8:15 it is translated in Wantoat as “salt.” (Source: Ronald D. Olson in Notes on Translation January, 1968, p. 15ff.)
See also leaven (1Cor 5:6).