There are seven full mouth letters in Arabic, which require a full mouth and emphatic pronunciation. These letters are commonly known as bold or heavy letters. In Arabic, these seven letters are called Huroof Al-Tafkheem. These heavy letters represent a distinctive feature of Tajweed.
Full mouth letters
Seven Full Mouth letters:
خ – Kha
ص – Suaad
ض – Duaad
ط – Tua
ظ – Zua
ع – Aeen
غ – Ghaeen
ق – Qaaf
Additionally, the letter Raa (ر) is also considered a full-Mouth letter when it meets any of the following four conditions:
1 – When ‘Ra’ has a Fatha on it.
إِنَّه لَقَوْلُ رَسُوْلٍ کَرِیْمٍ
2 – When ‘Ra’ has a Dammah on it.
وَاِذَالْبِحَارُ فُجِّرَتْ
3 – When ‘Ra’ has a Sukoon preceded by Fatha.
وَأَخْرَجَتِ الْأَرْضُ
4 – When ‘Ra’ has a Sukoon preceded by Dammah.
سَنَسِمُه عَلَی الْخُرْطُوْمِ
'Ra' (ر) should be pronounced lightly in two conditions:
1 – When ‘Ra’ has a Kasrah on it.
وَلَا نُشْرِکَ بِهٖ
2 – When it has a Sukoon preceded by Kasrah.
وَاستَغْفِرْہُ
To gain a better understanding of Quranic Tajweed,Enroll in our Tajweed Course.