word-meaning
This is not the first time that I see people refer to money as "box" (see here 0:12)
I searched in my dictionary and I didn't find a meaning like that, so I think about two options:
a) Maybe there's another word which sounds similar but is written differently.
b) It's the word and it's not in all the dictionaries
NOAD lists three definitions for shoulder (I've omitted Definition #1, as that is the classic anatomical shoulder):
2 a part of something resembling a shoulder in shape, position, or function : the shoulder of a pulley.
• a point at which a steep slope descends from a plateau or highland area : the shoulder of the hill sloped down.
3 a paved strip alongside a road for stopping on in an emergency.
With those definitions in mind (particularly the subdefinition under Def. 2), it seems like shoulder tells a bit more about the hill than side might; specifically, it implies the top of the hill is relatively flat, with a relatively steep slope downward from the top. Depending on their shapes, some hills might not have shoulders.
In regards to the sentence, I think the shoulder of the hill is a more precise area than the side of the hill. Looking at the image below, I there are several hobbit holes in the side of the hill, but only the ones boxed in orange are ones that I would place on the shoulder of the hill, that is, in the area where the slope descends downward from the highland area:
Unless Mr. Baggins lived in one of the lower holes, I wouldn't really call this a "mistranslation" – just a word that is perhaps more detailed than it needs to be.
If you want a word that is non-angry, long, and boring, then tirade is not it. The dictionaries aren't wrong. A tirade is given in anger.
Perhaps you're thinking of the third sense of Merriam-Webster's definition of monologue:
3 : a long speech monopolizing conversation
// I stifled a yawn as she continued her monologue about her vacation experiences.
This has the advantage of being applicable to both speech and text.
Or, there's the verb drone:
b : to talk in a persistently dull or monotonous tone
// droning on and on about his health
However, this one is applicable only to speech.
Best Answer
It is not 'box', it is 'bucks', an informal term for USD, Indian Rupee and a few more currencies.
I had read somewhere that originally 'buck' referred to deer i.e. money given to buy/exchange deer skin in ancient times.