Arabic diacritics

The Arabic script has numerous diacritics, which include consonant pointing known as iʻjām (إِعْجَام, IPA: [ʔiʕdʒæːm]), and supplementary diacritics known as tashkīl (تَشْكِيل, IPA: [t̪æʃkiːl]). The latter include the vowel marks termed ḥarakāt (حَرَكَات, IPA: [ħæɾækæːt̪]; sg. حَرَكَة, ḥarakah, IPA: [ħæɾækæ]).

The Arabic script is a modified abjad, where all letters are consonants, leaving it up to the reader to fill in the vowel sounds. Short consonants and long vowels are represented by letters, but short vowels and consonant length are not generally indicated in writing. Tashkīl is optional to represent missing vowels and consonant length. Modern Arabic is always written with the i‘jām—consonant pointing—but only religious texts, children's books and works for learners are written with the full tashkīl—vowel guides and consonant length. It is, however, not uncommon for authors to add diacritics to a word or letter when the grammatical case or the meaning is deemed otherwise ambiguous. In addition, classical works and historical documents rendered to the general public are often rendered with the full tashkīl, to compensate for the gap in understanding resulting from stylistic changes over the centuries.

Moreover, tashkīl can change the meaning of the entire word, for example, the words: (دِين), meaning (religion), and (دَين), meaning (debt). Even though they have the same letters, their meanings are different because of the tashkīl. In sentences without tashkīl, readers understand the meaning of the word by simply using context.

The literal meaning of تَشْكِيل tashkīl is 'formation'. As the normal Arabic text does not provide enough information about the correct pronunciation, the main purpose of tashkīl (and ḥarakāt) is to provide a phonetic guide or a phonetic aid; i.e. show the correct pronunciation for children who are learning to read or foreign learners.

The bulk of Arabic script is written without ḥarakāt (or short vowels). However, they are commonly used in texts that demand strict adherence to exact pronunciation. This is true, primarily, of the Qur'an ⟨ٱلْقُرْآن⟩ (al-Qurʾān) and poetry. It is also quite common to add ḥarakāt to hadiths ⟨ٱلْحَدِيث⟩ (al-ḥadīth; plural: al-ḥādīth) and the Bible. Another use is in children's literature. Moreover, ḥarakāt are used in ordinary texts in individual words when an ambiguity of pronunciation cannot easily be resolved from context alone. Arabic dictionaries with vowel marks provide information about the correct pronunciation to both native and foreign Arabic speakers. In art and calligraphy, ḥarakāt might be used simply because their writing is considered aesthetically pleasing.

An example of a fully vocalised (vowelised or vowelled) Arabic from the Bismillah:

بِسْمِ ٱللَّٰهِ ٱلرَّحْمَٰنِ ٱلرَّحِيمِ
bismi l-lāhi r-raḥmāni r-raḥīm
In the name of God, the All-Merciful, the Especially-Merciful.

Some Arabic textbooks for foreigners now use ḥarakāt as a phonetic guide to make learning reading Arabic easier. The other method used in textbooks is phonetic romanisation of unvocalised texts. Fully vocalised Arabic texts (i.e. Arabic texts with ḥarakāt/diacritics) are sought after by learners of Arabic. Some online bilingual dictionaries also provide ḥarakāt as a phonetic guide similarly to English dictionaries providing transcription.