Noon Saakin means a Noon with a Jazm/Sukoon on it. Tanween means Double Short Vowels. There are four rules related to Noon Saakin and Tanween. the rules apply on the characters that appear after Noon Sakin and Tanveen. the four Rules are: 1. Izhar. 2. Iqlaab. 3. Idhghaam 4. Ikhfa
1. Izhar. when there is any of the above letters of the throat after Noon Saakin or Tanveen. izhar will take place. Izhar means “Clear” we pronounce the “n” sound of the noon Sakin or tanween without pulling and Ghunna.
2. Iqlaab. If “ب” (Baa) appears after the Noon Saakin or Tanween, Iqlaab will take place. Iqlaab means to change the sound of “ن” of Noon Saakin or tanween into a hidden meem.The sound of noon “ن” of noon saakin “نْ” or tanween changes into meem “م” sound and Ghunna (Nasal Sound) will be done on the meem ” م ” . in some scripts a small meen ” نۢ ” is written to denote that noon ” ن ” changes into meem ” م ” . The examples: أَلِيمٌ بِمَا مِن بَعْدُ 3.
3.Idghaam (merging/combining). if any of the letters of يرملون appears after Noon Sakin or Tanveen, idghaam will be done. Idghaam means to merge the “ن” sound of the Noon Sakin or tanween with the following letter(must be one of يرملون letters “ی ر م ل و ن”). 1: if any of these four letters “يومن” comes, Idghaam will be done with Ghunna (the “ن” sound of Noon Sakin or Tanveen will be merged with one of the four letters”یومن” and also ghunna will be done with it). Examples with ghunna: مَن يَقُولُ مَن يُفْسِدُ if any of the two letters “ل ر ” (Laam ” Raa) comes, Idghaam will be done but without Ghunna. Examples without ghunna: يَوْماً لاَّ مُصَدِّقاً لِّمَا
4. Ikhfaa (to hide) (Ikhfa is going to hide “n” sound): if any of following fifteen ( ت ث ج د ذ ز س ش ص ض ط ظ ف ق ك) letters appears after Noon Saakin or Tanween, ikhfa will be done. Ikhfa means to slightly “ hide” , when you see any of these letters,make a light nasal sound and lengthen for 1 second. remember to hide the “n” sound from the Noon sakin and Tanveen. the Ghunna for the Ikhfaa: 1. Heavy Ghunna 2. Light Ghunna The Heavy Ghunnah غنۃ مفخۃ if any of the following heavy “Full-Mouth” Round-Mouth”( ص،ض،غ،ط،ق،ظ) letters appears after Noon Sakin or Tanveen the Sound of Ghunna will be heavy : The Light Ghunna: غنہ مرققۃ if any of the light ( ت ث ج د ذ ز س ش ك) letters appears after Noon Sakin or Tanveen the Sound of Ghunna will be heavy :