In the technical usage intended here, the unlettered person is one who cannot properly recite al-Fātiḥah—that is, he cannot recite it correctly, whether from memory or from a copy of the Quran. Even if he can read the entire Quran but cannot properly recite al-Fātiḥah, he is considered unlettered.

Al-Fātiḥah is the surah that begins, “All praise is due to Allah, Lord of all worlds.” [al-Fātiḥah] It is called al-Fātiḥah—the Opening—because the Noble Quran begins with it. It also has several other names.

“Or assimilates therein what should not be assimilated, or substitutes a letter, ...”

His statement, “or assimilates therein what should not be assimilated,” means that he assimilates in al-Fātiḥah something that should not be assimilated.

The scholars classify assimilation into major and minor. If one assimilates a letter into an identical letter, this is minor assimilation. If one assimilates a letter into one that is similar to it, this is major assimilation. But if one assimilates a letter into another that is neither similar nor identical to it, this is an error.

An example is the verse, “All praise is due to Allah, Lord of all worlds,” where he assimilates the hāʾ into the rāʾ. This is invalid assimilation, because the hāʾ is far removed from the rāʾ. Such a person is considered unlettered, even if this is the only way he is able to recite it.

The reason for this is that, by assimilating into it what should not be assimilated, he has omitted the letter that was assimilated.

As for the assimilation of letters that are close in articulation, an example is assimilating the dāl into the jīm in “qad jāʾakum.” There is a recognized recitation with this assimilation, though the well-known recitation is to pronounce both letters distinctly: “qad jāʾakum.” Yet if someone says “qaj-jāʾakum,” assimilating the dāl into the jīm, he is not considered unlettered. However, there is nothing in al-Fātiḥah comparable to “qad jāʾakum.”

His statement, “or substitutes a letter,” means that he substitutes one letter for another. This is the person with a speech impediment,