The Spanish word 'ayllu' comes directly from the Quechua word 'ayllu', which refers to a traditional extended family group or community. This is one of many words that Spanish borrowed from Quechua, the main indigenous language of the Inca Empire, as the Spanish colonizers encountered and adopted concepts from Andean social organization.

Since 'ayllu' is a direct borrowing from Quechua into Spanish, there aren't any simpler or more common Spanish words that are etymologically related to it. This term remains quite specific to describing traditional Andean social structures.

There are no etymologically related English words to 'ayllu', as it comes from Quechua, an indigenous South American language family that developed independently from Indo-European languages like English and Spanish. The concept is usually translated in English as 'extended family group' or 'community'.