Thank you SuStel and De'vID for replying. I think that finally I understood the source of my confusion. SuStel:
Your proposed sentence has four independent clauses in it. Are you sure 'e' vImaS is referring to the correct clause?
Initially I didn't understand this. But then I read De'vID's comment:
The problem here is that the {'e' vImaS} is too far away from the {tlhIngan Hol vIghoj}, so that it sounds like {tlhIngan Hol vIghoj} is a statement of fact, not a preference. One is inclined to interpret this literally as "I learn Klingon; I prefer that it replaces that I learn Vulcan" (i.e., you're learning Klingon, and you prefer that this was instead of Vulcan, maybe rather than instead of something else like Romulan or something). It's very confusing.
Then I realized, that perhaps the mistake I was making was taking the {'e' qa'} construction and using it as a whole, placing at the end the {'e' vImaS} believing that everything was clear. I hadn't realized that things would be so complicated. De'vID:
Why don't you just use the noun form of {'e' qa'}? {tlhIngan Hol vIghoj 'e' vImaS; vulqangan Hol ('e') qa'} "I prefer that I learn Klingon; it replaces Vulcan"
Indeed you're right! I totally forgot this option. Again, thank you for taking the time to clarify this. -- Dana'an https://sacredtextsinklingon.wordpress.com/ Ζεὺς ἦν, Ζεὺς ἐστίν, Ζεὺς ἔσσεται· ὦ μεγάλε Ζεῦ