Shadda, Tanvin, and Other Arabic Diacritics

Persian inherited its script and many learned words from Arabic, but it did not inherit Arabic case grammar or the full system of Qur'anic pointing. Most Iranian Persian is therefore printed without vowel marks. Two Arabic-derived marks nevertheless deserve active recognition: shadda or tashdidّ, which can signal a doubled consonant, and tanvinً, preserved in a limited set of Arabic adverbs and formulas.

These marks sit above or below a letter; they are not letters and have no isolated, initial, medial, or final joining shapes. The letter underneath still takes whatever joining form its position requires. For the basic short-vowel signs, see Vowel Signs for Learning and TTS.

A mark belongs to the preceding consonant

Persian runs right to left, but combining marks follow their base letter in the underlying Unicode sequence. Thus بَّ stores ب first and its marks afterward, even though the marks render around the same letter. Unicode normalization may canonically reorder two marks attached to that base, so do not infer storage order from their vertical appearance. You never type a mark as a separate right-to-left “letter before” the consonant.

Shadda: one written consonant, two timing units

Shadda tells you to hold or close the consonant twice as long. In Arabic loans this doubling can distinguish words, and many careful speakers preserve it. Ordinary Persian typography, however, often leaves shadda unwritten even when the pronunciation has a doubled consonant. Readers recover it from the known word, just as they recover short vowels.

The visual pair بنا / بنّا is especially useful: the consonant letters are identical. Only pointing separates benâ “building” from bannâ “builder.” In an ordinary unpointed sentence, context does the work.

In careful speech, dictionaries, primers, and religious or literary editions, a shadda may be shown: معلّم، مدّت، خطّ. In ordinary standard writing, معلم، مدت، خط are routine. In informal Tehran speech, the phonetic length of some doubled consonants may weaken, but spelling does not license a doubled letter. A word such as معلم is never written with two lams.

Tanvin: a small, closed class

The productive Arabic case system is absent from Persian. Iranian Persian nevertheless borrowed a set of adverbs already containing Arabic accusative tanvin, pronounced -an. Careful written forms include مثلاً masalan “for example,” واقعاً vâqe'an “really,” معمولاً ma'mulan “usually,” تقریباً taqriban “approximately,” and اصلاً aslan “at all.” The two strokes belong above the final alef; they are not a separate nun.

In everyday messaging, writers often omit the sign and type مثلا or واقعا. That is a real (informal) convention, not a different pronunciation. Edited (formal) prose normally retains the mark. The guide's display lines follow its guide-wide unpointed convention, while the learner reading still shows the pronounced -an ending.

Tanvin is not a general Persian adverb maker. Forms such as گاهاً occur in actual usage, but careful editors prefer the native adverb گاهی. There is no clean rule that lets a learner invent new tanvin adverbs: memorize the frequent established items.

Dammatan, kasratan, and Qur'anic signs

The other Arabic tanvin signs, ٌ -un and ٍ -in, do not form ordinary Persian words. They survive mainly in fully Arabic quotations and a few learned, formal or academic formulas such as مضافٌ‌الیه. Such expressions belong to a small inherited layer; do not apply Arabic case endings to Persian noun phrases.

Qur'ans and specialist editions can also contain a superscript alef ٰ, small recitation letters, elongation signs, and stop symbols. Those marks direct Arabic recitation, not Iranian Persian pronunciation. When quoting the Qur'an exactly, preserve the edition's pointing and recitation marks. When the same Arabic-origin word functions inside a Persian sentence, use normal Persian spelling and Persian syntax.

Common Mistakes

1. Doubling the letter instead of using or omitting shadda

2. Treating omitted shadda as permission to pronounce a different word

3. Creating a new tanvin adverb from a Persian word

4. Importing Arabic keyboard letters along with Arabic marks

Key Takeaways

Shadda can encode real consonant doubling even though normal Persian print often omits it. Fathatan survives as -an in a limited, memorized set of Arabic adverbs, while other Arabic case and Qur'anic marks belong to learned quotations and formulas. Persian readers recover much pronunciation from vocabulary and context: omitted marks are not missing consonant letters.