The alphabet, at a glance
Twenty-eight letters in their traditional order, with names, sounds, and the few quirks worth knowing on day one.
The Arabic alphabet has twenty-eight letters. They are written from right to left, and they connect to one another like English cursive. Of the twenty-eight, twenty-five are pure consonants. The remaining three — ا, و, and ي — are sometimes called the weak letters and double as the long vowels aa, uu, and ii. Short vowels are not written as letters at all. They appear, when they appear, as small marks above or below the consonants, and you will see them only in certain kinds of text. (See diacritics.)
Two ordering systems are in use. The alphabetical order — alif, baa, taa, thaa, jiim — groups letters by visual shape and is the order used in modern dictionaries. The older abjad order — alif, baa, jiim, daal, … — predates it, follows the order of the Phoenician alphabet, and is still used for numerology, list enumeration ("item alif, item baa, item jiim"), and some traditional contexts. The list below is in the modern alphabetical order.
The twenty-eight letters
The non-connectors
Most Arabic letters connect on both sides — to the letter before and to the letter after. Six letters break this rule. They connect to the letter on the right (the previous letter) but never to the letter on the left (the next letter). They are the one-way streets of the script: a word that contains them visually splits into segments wherever one occurs.
The six non-connectors are ا (alif), د (daal), ذ (dhaal), ر (raa), ز (zaay), and و (waw). When you see what looks like a gap in the middle of a word, that gap almost always falls just after one of these six. Once you have memorised them, the apparent fragmentation of Arabic words becomes predictable. See how letters connect for a fuller treatment.
The hamza
One mark on this list deserves a separate note: the hamza, ء. Phonologically, the hamza is the glottal stop — the catch in the middle of English uh-oh. It is a real consonant in Arabic and appears in ordinary words. Orthographically, however, it is treated like a guest. It does not have its own place in the alphabet and does not connect to anything. Instead, it sits on a "seat" — usually an alif (أ or إ), sometimes a waw (ؤ) or a yaa without dots (ئ) — or, in some positions, on the line by itself (ء). Which seat it takes depends on the surrounding short vowels, and the rules are notorious. In practice, learners memorise common spellings and pick up the system slowly.