The Spanish word 'mam' comes directly from the Mam language, where 'mam' means 'grandfather' or 'ancestor'. Mam is a Mayan language spoken in Guatemala and parts of Mexico. In Spanish, the word 'mam' is used to refer to either a person of the Mam ethnic group or to their language.

While 'mam' is a relatively uncommon word in Spanish, being specific to discussions of the Mam people and their language, there aren't any simpler or more common Spanish words that share its etymology, as it comes from a Mayan language rather than from Latin or Greek roots that are more common in Spanish vocabulary.

There aren't any common English words directly related to 'mam' through the Mayan etymology. However, it's interesting to note that the English word 'mama' and similar words for mother or grandmother in many languages, while sounding similar, are not actually related - they developed independently as early speech sounds that babies commonly make.