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:

    Human beings tolerate what they understand they have to tolerate.
    —Jane Rule (b. 1931)

    For all of us Frenchmen, the guiding rule of our epoch is to be faithful to France.
    Charles De Gaulle (1890–1970)

    Freedom prospers when religion is vibrant and the rule of law under God is acknowledged.
    Ronald Reagan (b. 1911)