Many Surahs (chapter) of the Qur’an begin with these isolated (disjoined) letters. They are believed to be symbols of mysteries, the meaning of which is known to Allah alone. There are about 20 different scholarly opinions based on guesswork.
There are only 14 letter of the Arabic Alphabets are involved always beginning of 29 out of 114 Surahs of the Nobel Qur'an with 14 unique combinations of two, three, four or five letters. The most frequent are ʾAlif Lām Mīm الٓمّٓ and Ḥāʾ Mīm حٰمٓ , occurring six times each and ʾAlif Lām Rā. الٓرٰ five times.
Each letter must be pronounced independently without of any vowel sound, except for letter Alif all remaining 13 letters must be pronounced with certain prolongation with its proper measure.