It seems likely that the Polynesian word(s) for sweet potato is a direct borrowing from Quecha. Beyond that I don't think there's accepted evidence for vocabulary exchange.
I gave it a check. It's hard to take a lot of conclusions from a single word, but
Quechua - kumar, khumara
Rapa Nui - kuma porá
Maori - kūmara, kūmera
Hawaiian - ʻuala
Tongan: kumala
This got to be at least two instances of borrowing, since either Rapa Nui picked another variant of the word to borrow or solved the issue with the ending consonant in a different way (by eliding it instead of adding a new vowel).
The Hawaiian cognate underwent /k/→/ʔ/ (spelled ʻ), so it's probably really old.
Based on that, if I had to take a guess: Polynesians contacted the Amerindians multiple times across the centuries, and it was kind of a big deal for Rapa Nui ones. Sadly a better analysis would need a bigger lexicon than a single word.
It seems likely that the Polynesian word(s) for sweet potato is a direct borrowing from Quecha. Beyond that I don't think there's accepted evidence for vocabulary exchange.
I gave it a check. It's hard to take a lot of conclusions from a single word, but
This got to be at least two instances of borrowing, since either Rapa Nui picked another variant of the word to borrow or solved the issue with the ending consonant in a different way (by eliding it instead of adding a new vowel).
The Hawaiian cognate underwent /k/→/ʔ/ (spelled ʻ), so it's probably really old.
Based on that, if I had to take a guess: Polynesians contacted the Amerindians multiple times across the centuries, and it was kind of a big deal for Rapa Nui ones. Sadly a better analysis would need a bigger lexicon than a single word.