Sun and Moon Letters - Rule

Rule

When followed by a sun letter, the l of the Arabic definite article al- assimilates to the initial consonant of the following noun, resulting in a doubled consonant. For example, for "the Nile", one does not say al-Nīl, but an-Nīl. When the definite article is followed by a moon letter, no assimilation takes place.

Sun letters represent all coronal consonants except ج ǧīm (see below). Since the article al- ends in a coronal consonant, it lends itself to assimilation with these sounds.

The sun and moon letters are as follows:

Sun letters
t d r z s š l n
Moon letters ء ه
ʾ b ǧ ʿ ġ f q k m w y h

Read more about this topic:  Sun And Moon Letters

Famous quotes containing the word rule:

    Roman, remember that you shall rule the nations by your authority, for this is to be your skill, to make peace the custom, to spare the conquered, and to wage war until the haughty are brought low.
    Virgil [Publius Vergilius Maro] (70–19 B.C.)

    As a rule we develop a borrowed European idea forward, and ... Europe develops a borrowed American idea backwards.
    Mark Twain [Samuel Langhorne Clemens] (1835–1910)

    Without doubt God is the universal moving force, but each being is moved according to the nature that God has given it.... He directs angels, man, animals, brute matter, in sum all created things, but each according to its nature, and man having been created free, he is freely led. This rule is truly the eternal law and in it we must believe.
    Joseph De Maistre (1753–1821)