The thing I observe is that the examples of Merriam-Webster where the English "so" functions as a conjunction, are the examples which if I was to translate in Klingon I'd use the {vaj}; but the {vaj} in Klingon is supposed to be an adverb and not a conjunction. On the other hand, I don't think any of the Merriam-Webster examples where "so" acts as an adverb could be translated by the Klingon adverb {vaj}.

So, either there's something here which I'm serious misunderstanding, or this is the case of another intentional attempt, to "alienize" a language crawling with terran puns.

The grammar is simply different.

In an English sentence like Be quiet so he can sleep, you have two independent clauses: be quiet and he can sleep. The word so joins them together with a connotation of purpose.

In Klingon, there are two ways to translate this. One is QonglaHmeH ghaH, yItam'eghmoH, and this is probably the more accurate translation, but this is not what we're talking about.

The other way to translate is is yItam'eghmoH; vaj QonglaH ghaH. This is two sentences, not one. The vaj is not a conjunction: it is an adverbial, telling us the manner in which the action occurs. It tells us that the ability to sleep occurs in the manner of a consequence. An alternative English translation of this Klingon might be Be quiet! He will be able to sleep as a result.

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SuStel
http://trimboli.name