Idgham

Definition of Idgham

Linguistically: insertion.

Technically: pronouncing two letters as a single doubled letter of the same kind as the second, or pronouncing a silent letter immediately followed by a voweled letter from the same articulation point, without separation.

The Causes of Idgham

Idgham has three causes:

Tamathul (Identity): the two letters are identical in name, script, articulation point, and quality — such as Faa with Faa in ﴾فَلاَ يُسْرِف فَِّي الْقَتْلِ إِنَّهُ كَانَ مَنْصُورًا﴿ (Al-Isra: 33)

or Baa with Baa in ﴾وَإِذِ اسْتَسْقَى مُوسَى لِقَوْمِهِ فَقُلْنَا اضْرِب بَِّْعَصَاكَ الْحَجَرَ﴿ (Al-Baqarah: 60)

Taqarub (Closeness): the two letters are close in articulation point and quality — such as Noon with Lam in ﴾أَلاَ إِنَّهُمْ هُمُ الْمُفْسِدُونَ وَلَٴكِن لاَّ يَشْعُرُونَ﴿ (Al-Baqarah: 12)

or close in articulation point only, such as Qaf with Kaaf: ﴾أَلَمْ نَخْلُقكُّم مِّن مَاء مَّهِينٍ﴿ (Al-Mursalat: 20)

or close in quality only, such as Lam with Raa: ﴾وَقُل رَّبِّ زِدْنِي عِلْمًا﴿ (Ta-Ha: 114)

Tajanus (Homogeneity): the two letters share the same articulation point but differ in quality — such as Taa with Daal in ﴾قَالَ قَدْ أُجِيبَت دَّعْوَتُكُمَا﴿ (Yunus: 89)

Note: there is a fourth quality that links letters — Tabaa'ud (remoteness), meaning a difference in both articulation point and quality. Unlike identity, closeness, and homogeneity, remoteness prevents Idgham and requires clear Idhar instead — such as Lam with Haa in ﴾قُلْ هُوَ اللَّهُ أَحَدو﴿ (Al-Ikhlas: 1)