Many Greek words found their way into the Latin language. How does accentuation work for these? Do you follow the Greek or Latin rules of accentuation. For example, as I was transcribing the Vestibulum, I came across the word nauclērus; this derives from the Greek word ναύκληρος. If you follow Latin rules, the accent will fall on the penult, whereas in Greek, on the antepenult.
So what is the correct way?
In general you should follow the Latin rules of accentuation. However, you’re correct that loan-words may behave in a deviant manner, and we have examples of this mentioned by the ancient sources. Over time (= when a word is accepted as a “true” Latin word) one expects some kind of levelling, as the Dreisilbenbetonung is such a strong feature of classical and even post-classical Latin.¹ In other words: something’s got to give so that this strong feature of the language isn’t disturbingly violated.
An example: fenestra is considered an Etruscan² loan (nothing like it is attested in our Etruscan corpus) mainly because we have proof (in Plautus) of the prevalent accentuation fénestra (which easily results in fénstra). In French we have fenêtre from fenéstra (providing it isn’t borrowed from Latin), so there may have been areal or other variation.
If you regard the Greek loan-words as Greek words, you should accentuate them in the Greek way. If they are in your opinion Latin (their origin in a way not mattering), pronounce them according to the well-known penult rule. English words like mise en scène and ennui (pronounced in the French manner) come to mind as analogical to the first group, egalitarian (adapted into English) from the second. I’m sure there are many better examples.
¹ That it is such a strong feature is indicated by the fact that all the Romance languages have inherited it. It is naturally sometimes very badly obfuscated (most strikingly in French) after many phonological changes.
² As far as we know, Etruscan had strong word-accent on the first syllable, like Czech, Finnish and Hungarian.
Thanks! That was very helpful and informative.