I have a question about -ngan inhabitant. I can't find the sentence discussion but somebody asked about the difference between Human and tera'ngan. (It wasn't a sentence discussion--I saw it elsewhere.) I believe someone answered that it is the difference between race and either where you inhabit or your planet of origin? But I generally see -ngan used as if it is talking about race.
So if a human were adopted by Klingons and lived his entire life on Kronos, is he a tera'ngan or a tlhingan? If he is still a tera'ngan then how is that different than Human; they would be synonyms. If he is a tlhingan, then how can you be sure anymore what the words tlhingan, tera'ngan, vulqangan, etc really mean?
Excellent philosophical questions. Perhaps different people use them in different ways. But regardless of that, we have two different words in English (human, earthling) and we have those same two words in Klingon (Human, tera'ngan). In this course we will not except translations of one for the other - we use a one-to-one correlation. I will leave it to others to debate whether the two words are used for different concepts in Star Trek and whether that is a proper differentiation or not.