In order to have great speech, three components are necessary: timing, content, and style. The moment must be opportune, the meaning must be of value and the wording and structure must melt together like honey on butter. Nothing else but this is found in the Quran!
Presumptuous? Boastful!… I only fear that this is an understatement. The timing and context of each verse are spot on and it is also timeless; the content and meaning are of the utmost value and the ultimate truth; the only difficulty encountered is explaining the Quran in its style.
Since the Quran is in Arabic, it is possible to translate its meaning, but impossible to translate its style. Imagine translating poetry (the words of Allah are greater than poetry) of one language to another; you would lose the rimes, the rhythm, and cohesion. Regardless, metaphors, oxymora, and organization would all be kept; but you would not appreciate it as much. In my opinion, if one really wants to get a sense of the richness in style of the Quran that is unmatchable, one could listen to Nouman Ali Khan. He explains in great detail (way better than I ever could), in English, the greatness of the words of Allah on the style aspect.
After one gets a sense of all this, one cannot imagine the Quran being revealed in another language other than Arabic.
Linguistic Miracle of the Quran