The Holy QURAN is the word of ALLAH for the whole Mankind. When you see and read the Quran then you realize that Not only that is the Book for the whole world but also the language of the QURAN is miraculous. Talking about QURAN, It is in the Arabic Language, which means that it is not understood by the whole mankind even at this time so why this book was revealed In Arabic Language. You can learn Arabic from the Online Quran Academy
The language of time
The simplest answer to this question would be that, it was revealed at the time and to the people who were speaking Arabic language. The prophet Muhammad Peace Be upon him was the prophet through whom, this book was revealed to the whole world. He was part of the people who were fluent Arabic and he himself was the Arabic speaker, so he would have been able to understand the language and also explain it to the world.
Miraculous in nature
Once The prophet Muhammad Peace Be upon him has said that I have given the miracle which is the book of ALLAH. Now you would say that Moosa (a.s) and other prophets had miracles like making the stick the snake and Making people alive after death. But how the book can be miracle. Well it’s very miraculous in nature because, in other miracles you can see and understand the miracle but here you can’t totally comprehend the language of the QURAN until you are totally experienced in the following language. No wonder the Arabic people of today knows QURAN more than non-Arabic. As they know the things which are miraculous in nature and hidden behind the words which cannot be understood by the person.
Difference with other books
Even though there can be many reasons for revealing the QURAN in Arabic but in real sense the important thing is that you read and comprehend the message in the book for betterment of the mankind.
Still one more reason of having this book in Arabic would be that to make it different than other holy books. The Bible was in Hebrew but the QURAN is in Arabic. That book was for a set of time for specific people whereas this book is till the last day of the world and for the whole mankind, not for specific part of the world or people.
Though, there are many experts in the field of other languages but when you talk about Arabic language then not only it’s one of the best languages in the world but also so deep in nature that every word or letter can put you in the other parts of the world. I hope you got the idea about this thing and if you want more then ask Online Quran Academy. https://quranonlineacademy.org/ is going to provide you with more answers and the deep understanding of Arabic language. If you will learn the Arabic language then one thing is for certain that you will be able to not be confused after reading some passages of the QURAN and the added attraction would be that you will guide other persons to the right meaning of the QURAN and have the blessed life and Hereafter.