How sophisticated is the language in your own world, or the worlds of your favorite authors?
For my largest fantasy world I invented two languages, neither of which I wanted to be translatable directly into any European language. As far as sophistication goes, neither is very complex, which makes sense in the context. The languages themselves are still in primitive form, having been invented by nomadic herds/packs of sentient dinosaurs only six centuries prior to the story's beginning.
In the first language the rules are as follows:
Words fall into two categories: nouns and verbs. Descriptives are formed by modifying the closing syllable of either a noun or a verb (you use a different modifying syllable for a verb than you would for a noun). There is also an appendable syllable for plurals, which can be attached either to the beginning or end of any word; when used on nouns this syllable indicates simple plurality, when used on verbs it implies superlative form, when used in conjunction with the descriptive modifying syllable, the word can take on new meanings all together depending on context.
Plain verbs are conjugated according to the speaker's bearing in respect to the object of the verb (going from the assumption that these dinosaurs can sense the planet's magnetic field like birds do). Verbs always follow their objects. Other than that, sentences can be arranged pretty freely. Adjectives and adverbs can be compounded at will to any noun or verb they apply to, and at either end of that noun or verb.
I only have about 200 words invented for this language. Most prevalent sounds are: a, b, w, u, r, and l.
The second language is even rougher than the first, having been developed more recently, therefore having had less time to evolve.
Sentences do not exist. The language is composed entirely of one-syllable combinations of the letters s, r, g, t, k, 'th', 'sh', 'zh', and n, with appropriate vowel sounds connecting them. Each syllable carries anywhere from one to ten associated meanings, not necessarily of any traditional word classification. Syllables combine to form words, which tend to be fairly short (if they were long it would be nearly impossible to deduce meaning from them). Syllables go into the word in any order the speaker cares to put them, with a connective vowel sometimes being inserted between two syllables when speaking them in succession would be impossible (sometimes adding the connective vowel can result in a sound that resembles one of the meaningful syllables, in this case it is up to the listener to either ask for clarification or decipher the speaker's intention from context). This language has its origins in pre-civilized hunting packs, where nothing very complex needed to be said. It's growth into a language in it's own right came after a political division that resulted in one of the saurian species forming a nation separate from--and in opposition to--the others.
There is a third language, spoken only by the warrior class within the larger empire. It consists of body movements and animal sounds, and only reaches true sophistication during combat, when the warrior's opponent becomes an integral part of communication with allies. There is little attempt to describe the various component movements in the books, as it would be nearly impossible to translate for anybody who was not born/hatched into the class that speaks it (and the viewpoint characters are foreigners altogether).