"Only few Terrans are brave."
Translation:yoH tera'nganpu' puS neH.
I've got a problem with this sentence. The neH here is obviously being applied to the puS: the meaning of the sentence is that only a few Terrans, not a lot of Terrans, are brave. But neH is an adverbial that comes after the noun or verb it modifies. It can't modify verbs acting as adjectives, and even if it could, puS neH means merely few, meaning it trivializes the fewness. As given in the lesson, this sentence really means Only the few Terrans, and nobody else, are brave.
It's a subtle point. Imagine the descriptor were Quch be happy instead of puS be few. yoH tera'nganpu' Quch neH Only the happy Terrans are brave. It doesn't imply that there are brave, happy Terrans, and cowardly, unhappy Terrans; it implies that there are some happy Terrans who are brave, and then there is everyone else. Maybe there is a group of happy Terrans, sad Terrans, happy Klingons, and sad Klingons. yoH tera'nganpu' Quch neH means that only the happy Terrans of the group are brave, and the sad Terrans, happy Klingons, and sad Klingons are not brave. Now go back to puS. Suppose there is a group divided into sub-groups: a few Terrans, a lot of Terrans, a few Klingons, and a lot of Klingons. yoH tera'nganpu' puS neH means only the group of a few Terrans is brave; the many Terrans, the few Klingons, and the many Klingons are cowardly. The sentence doesn't mean what you want.
I'm not sure what the lesson focus of this sentence is. If it's drilling neH, then I recommend replacing puS with a different verb, like Quch, that doesn't produce a false English meaning.
I was surprised by the neH applied to the adjective, and was going to ask about that. Perhaps it's intended to modify the entire noun phrase tera'nganpu' puS, but that still doesn't make much sense to me.
After some exploring in boQwI', I've found a lot of examples using neH to mean "solely", like you've said. I think this sentence would make more sense without neH at all. Nothing is being trivialized by the English sentence beyond the use of the word "few". "Only" seems to be a grammatical artifact.
Unlike the other adverbials, (neH) follows the verb which it modifies. The semantic effect is one of trivializing the action.
qama' vIqIppu' neH I merely hit the prisoner. (qama' prisoner, vIqIppu' I hit him/her*)
Duj yIQotlh neH Just disable the ship! (Duj ship, vessel, yIQotlh disable it!)
The use of neH in the preceding sentence implies that the ship is to be disabled, but not damaged further.
Also unlike the other adverbials, neH can follow a noun. In such cases, it means only, alone.
yaS neH only the officer, the officer alone
jonta' neH only the engine
It's not so much "at the end of the sentence" as "after the noun" (in this case, the noun phrase tera'nganpu' puS), where neH means "only" or "alone".
After the verb, it trivialises the action: qama' vIqIppu' neH "I merely hit the prisoner" (I didn't kill him, just hit him).
Regardless of any problems with the Klingon, I'm not sure "Only few Terrans are brave." is grammatical English. (If it is, I think it means "Terrans are only brave when they are few", which... might in fact be a possible interpretation of the Klingon, I'm not sure, but it probably isn't what was meant.)