Some surahs begin with disjointed letters, such as «الم» or «حم». These letters are not read as one ordinary word. Each is pronounced by its Arabic letter-name. A pronounced name may contain a madd or lin letter, making special prolongation rules relevant.
«الم» is read as the letter-names alif, lam, mim.
«حم» is read as ha, mim.
The written symbol and the full sound of its name are not identical. The symbol «م» is named «ميم», which includes madd ya. Correctly hearing and pronouncing these names reveals where elongation and a final still consonant occur. Determining the ultimate meaning of the disjointed letters is not necessary for their phonetic rules.