Sun and moon letters
Arabic · Key Stage 2 · The School
The written word and the spoken word differ
Arabic writes the definite article as alif-lam before a noun, but it is not always SAID as it is written. Before some letters the lam disappears in speech and the following letter doubles instead. This is a rule about pronunciation only — the spelling never changes — and it is one of the first things that separates reading Arabic from decoding it.
Sun letters swallow the lam
The SUN LETTERS are fourteen letters made near the front of the mouth, in the same region as lam. Before one of these, the lam is not pronounced and the letter after it is doubled, marked by a shadda. The rule is named after the word for sun itself, which begins with one of them and is pronounced ash-shams, never al-shams.
Moon letters keep it
The other fourteen are MOON LETTERS, and before them the lam is pronounced normally. The word for moon begins with one of these and is read al-qamar, with the lam clearly heard. So the two example words are the memory aid: whatever happens to the article in shams happens with every sun letter, and whatever happens in qamar happens with every moon letter.
الشَّمْس is written with ال and pronounced ash-shams — the ل is silent and the ش doubles, which the shadda shows. القَمَر is written the same way and pronounced al-qamar — the ل is heard. ش is a SUN letter and ق is a MOON letter. Now try الرَّحْمٰن (ar-raḥmān) and البَيْت (al-bayt). The spelling never changes; only the sound does.