The Spanish word 'boniato', meaning 'sweet potato', comes directly from the Taíno word 'bonyata' with the same meaning. Taíno was the principal language of the indigenous peoples of the Caribbean when Spanish colonizers arrived in the Americas. Many food words in Spanish, particularly those referring to crops native to the Americas, were borrowed from Taíno.

Since 'boniato' comes from Taíno, there aren't any simpler or more common Spanish words that share its etymology. However, Spanish speakers might also use the more common word 'batata' or 'camote' to refer to sweet potatoes, though these come from different etymological origins.

There aren't any common English words directly related to 'boniato' since it comes from Taíno. While English has the word 'sweet potato', this is etymologically unrelated, being a compound of the Germanic-derived 'sweet' and the English word 'potato', which comes from Spanish 'patata', ultimately from another Taíno word 'batata'.