Identical Letters (Tamāthul)

Introduction about relations between letters

When any two letters meet—whether in the same word or across two words—there must exist a specific relationship between them. This relationship falls under one of four types: identity (tamāthul), closeness (taqārub), similarity (tajāns), or dissimilarity (tabāʿud). The first three are causes for assimilation (idghām), while the fourth necessitates clear pronunciation (iẓhār). The types of assimilation between letters will be clarified in this and upcoming lessons, InshAllah.²

Introduction about Idghām:

Linguistically, idghām means 'insertion.'

In technical terms, it is the merging of a non-voweled (sākin) letter into a voweled one, so that they become one letter, that is doubled and pronounced as a single letter from the identity of the second letter.

The benefit of idghām is to ease the pronunciation of the letters, as pronouncing one letter is easier than two

Idghām caused by meeting letters falls into three types: idghām of identical letters (mutamāthilayn), similar letters (mutajānissayn), and close letters (mutaqāribayn). This lesson will focus on assimilation of identical letters (idghām al-mutamāthilayn).³

First: Definition and Ruling of Tamāthul

Tamāthul (Homogenity) refers to the relationship between two letters that are the same in both articulation point and attributes—in other words, the same letter, like when a Meem is followed by another Meem. When such a case occurs with the first letter being non-voweled and the second voweled, they are assimilated into one doubled(mushaddad) letter.

Second: Instances in the Qur’an

Tamāthul may occur within a single word or across two words:

* Within one word, such as: ﴿يُدۡرِككُّمُ﴾ in: ﴿أينما تكونوا يُدۡرِككُّمُ المَوت﴾, where a non-voweled kāf is followed by a voweled kāf. We pronounce them as one doubled kāf: (yudrikkum).

* Across two words, such as: ﴿اذْهَب بِّـكِتَابِي﴾, where a non-voweled bāʼ is followed by a voweled bāʼ. It is pronounced as a one doubled bāʼ: (idhhabbikitābī).

Tamāthul is the strongest cause of assimilation. Whenever two identical letters meet—first non-voweled, second voweled—assimilation is obligatory, regardless of whether they appear in the same word or across two words.⁴

Third: Examples from the Qur’an

Fourth: Important Notes

1. The joining of an elongated wāw (non-voweled) followed by a wāw with harakat(non-elongated)does not count as tamāthul, e.g., ﴿ءَامَنُواْ وَعَمِلُواْ﴾, because they do not share the same articulation point as we studied previously is Makharej lessons. The same applies to elongated yāʼ followed by yāʼwith harakah, e.g., ﴿ٱلَّذِي يُوَسۡوِسُ﴾.

2. There is one instance in the Qur’an where both assimilation and clarity are allowed between two identical letters, that is in accordance to the narration. It occurs between the two hāʼs in: ﴿مَآ أَغۡنَىٰ عَنِّي مَالِيَهۡۜ هَلَكَ عَنِّي سُلۡطَٰنِيَهۡ﴾ [Al-Ḥāqqah: 28–29]. The first hāʼ (hāʼ of silence(Sakt)) is non-voweled and is followed by a voweled hāʼ. There are three valid ways to recite this:

A - Silence with clarity(iẓhār): a short pause without breathing on the hāʼ in (māliya), then moving to the next word. This is the preferred recitation.

B - Stop with clarity(iẓhār): a short pause with breathing on the first hāʼ , then proceeding to the next word.

C - Merge the two verses with assimilation of both hāʼs.