How do we respond to those who cast doubt upon the sanctity of the Holy Qur’an by claiming the existence of superfluous letters within it?

Superfluous letters in language often serve to emphasize meaning, falling under the category of increasing meaning by increasing the structure, and are sometimes called "silah" (connective). As for the disconnected letters at the beginning of some Quranic surahs, they are among the manifestations of the miraculous nature of the Holy Quran. They indicate that the Quran is composed of the very letters that Arabs use in their speech, yet they are incapable of producing anything like it. Therefore, the surahs that begin with these letters often subsequently mention the triumph of the Quran and explain its miraculous nature.