Sr. Ume Aimon,
The reason of Arabic speaking peoples not understanding the Qur’an is cited by Dr. Shabbir in QXP. He quotes Allama Ahmad Amin Al Masri as saying, "Persian literature gave an entirely alien complexion to Arabic linguistics". (Fajril Islam).
To realize the magnitude of this statement, you will just have to do a little exercise: pick out some Urdu words that originally came from Arabic, and compare the Urdu meaning with the Arabic one. You will be surprised as to how much the meanings differ! In fact, I used to be very curious about this disparity until I read Allama Masri’s statement. Since Urdu is influenced by Persian to a great degree, the Urdu meanings of many Arabic-origin words have acquired a totally different meaning from the original Arabic! Another exercise: go to dictionaryDOTcom and search for a random word. If the word’s origin is in Latin, notice how the meaning in today’s English differs from the original Latin meaning. (“Lost in Translation” would be a very apt term here). You will probably have to input 10-15 words to gain a feeling of how languages tend to have their individualities compromised over the course of time.
Indeed, the “infiltration”, if you will, of foreign languages into any given language changes the hue of the language and gives it a very foreign complexion. In the case of Arabic vs. Persian, Arabic was purposely given an “alien complexion” by the Persian “Imams” with the express purpose of rendering a mystifying feeling to the otherwise straightforward message of the Qur’an.