{tlhIngan Hol vIparHa', 'a black speech vIparHa'qu'}.

"I love black speech more than klingon".

Why not translate Black Speech as Hol qIj?

"very/more" 'oSbe'bej {-qu'}; laDwI'vaD emphasis yajmoH mojaqvam 'e' vISov. 'a "emphasis" majatlhtaHvIS, ghurbogh vay' wIDel, qar'a'?

-qu' is what is known as an intensifier. Very is just one example of an intensifier; really is another. See the page I linked for a whole bunch of examples. That tea is very hot; That tea is ridiculously hot; That tea is terribly hot; That tea is totally hot; That tea is excessively hot; That tea is insanely hot — all of these mean tujqu' Darghvetlh.

-qu' doesn't mean more; that meaning just comes implicitly from the comparison you made between Klingon and the Black Speech. I like Klingon, but I really like the Black Speech, so obviously I like the Black Speech more. The more comes from the combination of but and really, but it's not actually stated.

jIqon: {pIj bISuvvIpchoHba'}; nuq jatlh mu'tlheghvam?

You obviously often become afraid to fight.

1. Often you are obviously, afraid to fight.

2. Obviously, often you are afraid, to fight.

What happened to the begin part?

3. You obviously, often begin, to be afraid to fight.

4. Obviously you begin, that you are often afraid to fight.

5. Obviously you begin to be afraid to often fight.

I feel fairly confident that Klingons would consider this to be splitting hairs. When you've got a real context, the exact meaning of the sentence will be clear. It doesn't necessarily mean exactly one or exactly all of these things; it carries all of these meanings, but the precise interpretation is left to the context to unlock.

I think this is typical of Klingon grammar. It only gives you what you need to understand the sentence. It's not as precise as many other languages. I consider this one of its strengths: if you're paying attention, you can get across your exact idea while using only very broad strokes.

Consider the following:

DujDaj ra' HoD.

A simple, easy to understand sentence, right? Are you sure?

A captain commands his (own) ship.
A captain commands her (own) ship.
The captain commands his (own) ship.
The captain commands her (own) ship.
A captain commands his (someone else's) ship.
A captain commands her (someone else's) ship.
The captain commands his (someone else's) ship.
The captain commands her (someone else's) ship.
A captain commands his (own) ships.
A captain commands her (own) ships.
The captain commands his (own) ships.
The captain commands her (own) ships.
A captain commands his (someone else's) ships.
A captain commands her (someone else's) ships.
The captain commands his (someone else's) ships.
The captain commands her (someone else's) ships.
Captains command his (someone else's) ships.
Captains command her (someone else's) ships.
The captains command his (someone else's) ships.
The captains command her (someone else's) ships.

That's a lot of things this sentence could mean! English is more exacting than Klingon in this way, but give the Klingon sentence a context, and there's no question what it means.

Vixis has just been promoted to captain and has taken command of a ship. One of her new subordinates starts questioning her orders. She shouts at the subordinate, HItlhochQo'! HoD jIH! DujDaj ra' HoD. qara'DI', bIlobbej. cholobbe'chugh, HIchDalvo' qavo'. Now there is no question at all exactly what the sentence means.

{cha'logh bIHoSghajqu'choH}

mu'tlheghvam mughlu'taHvIS, wej DuH tu'lu':

1. Twice you become, very powerful.

2. You become very, powerful twice.

3. You become powerful, twice the {-qu'}.

You become very powerful, twice. Any further attempt to plug different bits of the sentence together for specialized meanings falls under what I called splitting hairs. If you can provide a context that would make some other combination make sense, I'd be willing to consider it.

For what it's worth, those times we've seen things like batlh bIHeghbe' You will die without honor, I don't think this is the rover being applied to the adverbial so much as the rover being applied to the entire sentence. It's not batlh[-be'] bIHegh<-; it's [batlh bIHegh]-be'. It's simpler than you're trying for.

-- 
SuStel
http://trimboli.name