Idghame Methlayn
Idgham means merging or adding something in something else. In tajweed, it means reading two similar letters that follow each other by combining pronounciation of the two letters in the second one.
IDGHAM E METHLAYN : If two letters, for which articulation points are the same, follow each other and the first one has no harakah while the second one has harakah, the one with no harakah is merged into the one with harakah.
If two letters have the same articulation points and the same attributes, they are called methlayn or “identicals”. If these letters come together in one word, they are written as one letter with shaddah.:
اَلْحُرُّ , رَبُّكَ
If they come together in two words next to each other, they are written seprately.:
عَنْ نَفْسٍ , فَمَارَبِحَتْ تِجَارَتُهُمْ
There are two forms of idgham e methlayn :
a) Idgham e methlayn with ghunnah (merging of identicals with nasal sound)
b) Idgham e methlayn bela ghunnah (merging of identicals wuthout any nasal sound)
Idghame methlayn bela ghunnah occurs when Noon without a harakah (ن)’ is followed by a Noon with a harakah; and Mem without a harakah (م)’ is followed by a Mem with a harakah. Ghunna is the nasal sound that comes when pronouncing certain letters.:
فىاﹶذَانِهِمْ مِنْ , وَمَنْ نُعَمِّرْهُ
Idgham e methlayn bela ghunnah occurs when all letters but (ن) and (م) follow each other the first one having no harakah while the second one has a harakah:
بَلْ لجُّوا , اَلاَّعِبُونَ