When talking in linguistics topics about the word "to be" and its foreign language equivalents like Spanish "ser" and "estar", the name of this kind of special verb is "copula".
But copula has two plural forms:
In a formal context as linguists might use, which sounds more "professional"? Does the Latin irregular seem "more correct and erudite" or "too pompous"?
Please note I'm not asking for prescriptive vs descriptive debate or plain vanilla "most frequent" as a simple Google Ngram would provide. As far as I'm concerned both are correct, I just want to narrow it down to how professionals use it in the given context.