The 14 sun letters are ت ث د ذ ر ز س ش ص ض ط ظ ل ن. When the article precedes them, its lām has no separate sound; the following consonant is pronounced in assimilated/geminated fashion.
In الشَّمْس hear the strengthened shīn; in النَّجْم hear the strengthened nūn. The lām remains written but is not independently released in connected speech.
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Fourteen sun letters
Idghām: Types, Complete/Incomplete Assimilation and the Definite Article
The 14 sun letters are ت ث د ذ ر ز س ش ص ض ط ظ ل ن. When the article precedes them, its lām has no separate sound; the following consonant is pronounced in assimilated/geminated fashion.
In الشَّمْس hear the strengthened shīn; in النَّجْم hear the strengthened nūn. The lām remains written but is not independently released in connected speech.