Let's assume the Quraninc initials (Muqatta'at) were some well-known abbreviations in Arabic among Arabs of the the Exalted Prophet's time.
But, today, when we read the translations of the Quran, we usually find the initials untranslated. In addition, Arabs of today no longer use or know these letters.
Now, if we would not have classical Arabic dictionaries that could explain the meaning of Muqattaat, then we had to admit we no longer can reach to the meaning of Muqattaat.
Result: we could not understand some verses (i.e. Muqattaat) of the Quran today.
Is it acceptable that we could not understand some verses that were understandable by the former audience?!
Are we expected to understand only those parts of the Quran that are understandable for us (through dictionaries, native Arabs people etc)?!
Again, Is it acceptable that we could not understand some verses (i.e. A.L.M. etc) that were understandable by the former audience?!
(Please forgive my repeat)