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)

    It is an endless and frivolous Pursuit to act by any other Rule than the Care of satisfying our own Minds in what we do.
    Richard Steele (1672–1729)

    Fatalism, whose solving word in all crises of behavior is “All striving is vain,” will never reign supreme, for the impulse to take life strivingly is indestructible in the race. Moral creeds which speak to that impulse will be widely successful in spite of inconsistency, vagueness, and shadowy determination of expectancy. Man needs a rule for his will, and will invent one if one be not given him.
    William James (1842–1910)