StealthToadWhat’s the difference between yams and sweet potatoes?
The name “yam” is used for a few different root vegetables.
The word is from West Africa and refers originally to Dioscorea yams, which are found in many parts of the world — having been independently domesticated in Africa, Asia, and the Americas. The word “yam” is related to the Fulani word for “to eat”, and was introduced into European languages by way of Portuguese colonizers.
But in the US, “yam” almost always refers to a variety of sweet-potato (Ipomoea genus), which is more closely related to a morning-glory flower than to either Dioscorea or a true potato (which is a Solanum nightshade).
Both sweet-potatoes and potatoes are native to the Americas. Sweet-potatoes probably were grown first in the Yucatán or in eastern South America, while true potatoes are from Peru and western South America.
Meanwhile in New Zealand, a “yam” is oca, an Oxalis species — close relatives of sourgrass and redwood sorrel. And in Malaysia, “yam” is taro root!
LvxferreThe word “yam” is related to the Fulani word for “to eat"
The etymology is a bit messy. It might be from Fula, but it’s probably from Wolof ⟨ñàmbi⟩. Nowadays the Wolof word means yucca, but given that yucca is from the Americas, odds are that it was originally used for any edible root; or potentially another local root.
Either way (from Fula or Wolof), the word ended in Portuguese as ⟨inhame⟩ [i’ɲã.me]. Nowadays it refers to taro, but before that English borrowed ⟨inhame⟩ as ⟨yam⟩.
Nowadays the Wolof word means yucca, but given that yucca is from the Americas, odds are that it was originally used for any edible root; or potentially another local root.
That reminds me of how the word “corn” referred to any grain until maize was discovered
Yup, it’s the same underlying phenomenon - as maize becomes the prototypical non-wheat cereal grain for plenty speakers, they eventually repurpose the word “corn” to mean exclusively “maize”. (British dialects are the exception that prove the rule, as maize isn’t so prevalent in the islands.)
This doesn’t happen just with crops, mind you - even animals get this treatment. Guarani ⟨jagua⟩ for example went from “hunting beast, specially jaguar” to “dog”, while Navajo ⟨łį́į́ʼ⟩ went from “pet, livestock, specially dog” to “horse”.