Solar vs. Lunar Letters
28 consonant letters, 14 letters are called solar letters الحُرُوْفُ اَلشَّمْسِيَّةَ and 14
are called lunar letters الحُرُوْفُ اَلقَمَرِيَّةَ
This distinction is only for pronunciation of words starting with these letters
when prefixed with ال (the definite article)
Articulation of solar letters involves the tip of the tongue, e.g., ت, س, ش, ن, ر
Tip of the tongue plays no role for lunar letters, e.g., ب, ق, م, ك, و
When ال is prefixed to a noun beginning with a solar letter, the ل of the ال is
assimilated to the solar letter, e.g., al-shamsu is pronounced as ash-shamsu
The assimilation is indicated by the shaddah on the first letter of the noun
In writing, the ل is not assimilated, e.g., (الشَّمْسُ )
No such assimilation takes place for lunar letters, e.g., al-qamaru is pronounced
as al-qamaru (القَمَرُ)