(1) Idhlaq: Ease of letter production from tongue tip or lip.
6 letters in mnemonic "Firra min lubb" (فِرَّ مِن لُبٍّ): ف ر م ن ل ب
Three from tongue tip (ر ن ل), three from lips (ف م ب).
(2) Ismat: Heaviness of letter production from deeper organs.
22 letters — all others. Arabs avoided 4-5 letter Arabic words made entirely of Ismat letters.
Letter Titles:
- Jawfi (cavity): Madd letters ا و ي
- Halqi (throat): ء ه ع ح غ خ
- Lahawi (back tongue): ق ك
- Shajri (middle tongue): ج ش ي
- Asali (tongue tip): ص س ز
- Lithawi (gums): ث ذ ظ
- Nat'i (palate): ت د ط
- Dhawlaqi (tongue edge): ل ن ر
- Shafawi (lips): ب م و ف
- Hawa'i (nasal): ghunnah letters
Question: What are the six Idhlaq letters and the lexical benefit Arabs derived from them? What title is given to ص س ز?
Answer: Idhlaq letters: ف ر م ن ل ب — mnemonic "Firra min lubb". Benefit: native Arabic 4-5 letter words must contain at least one Idhlaq letter. Title of ص س ز: Asaliyyah (tongue tip)