A common assumption among people unfamiliar with South Asian languages: Sindhi and Urdu are basically the same script, the way British and American English use the same alphabet. The assumption is understandable. Both scripts are written right to left, both use Nastaliq calligraphic style in print, and both sit in the same Unicode blocks. But at the character level, the comparison holds only partially — and the parts where it breaks down are fundamental to how Sindhi sounds and means.
What They Share
Sindhi and Urdu share the core Arabic alphabet — the 28 letters that form the base of the Perso-Arabic script tradition. They also share most of the Persian additions that became standard in South Asian scripts: پ چ ژ گ. And they share the same directional writing system, the same connected cursive letter-joining rules, and the same Unicode bidirectional algorithm behaviour.
For common words borrowed from Arabic and Persian — which make up a substantial portion of both languages' formal vocabularies — the spelling is often identical. The Urdu word for "book" (کتاب) and the Sindhi word for "book" (ڪتاب) differ by exactly one character: Urdu's ک versus Sindhi's ڪ. The words are pronounced the same. But they are stored differently in Unicode.
Where They Diverge
Sindhi is an Indo-Aryan language with a phonological inventory shaped by its geographical and historical position at the intersection of South Asian and West Asian language areas. It has sounds that Arabic, Persian, and Urdu simply do not have — and when those sounds were mapped to the Perso-Arabic script in the 19th century, new letter forms were required.
Implosive Consonants
The most phonologically distinctive feature of Sindhi is its set of implosive consonants — sounds produced by a downward movement of the larynx that creates a distinctive "falling" quality. These are completely absent from Urdu.
| Sindhi letter | Sound | Urdu equivalent (different word) | Code point |
|---|---|---|---|
| ٻ | Implosive /ɓ/ | ب /b/ | U+067B |
| ڄ | Implosive palatal /ɗ̠/ | No equivalent | U+0684 |
| ڳ | Implosive velar /ɠ/ | گ /g/ | U+06B3 |
In Sindhi, ٻاپ (implosive b) means "father." باپ with Urdu's ب means something similar but is a different phonological form — and in careful Sindhi speech, the distinction is audible. Writing ب where ٻ is correct is not just a spelling error; it represents a different phoneme.
Aspirated Consonants
Sindhi distinguishes aspirated consonants — where a puff of air follows the consonant — as separate phonemes. Urdu represents aspiration differently: it uses the letter ہ after a consonant as an aspiration marker. Sindhi has dedicated letters for many aspirated sounds:
| Sindhi | Represents | Urdu writing of same sound |
|---|---|---|
| ٿ | Aspirated retroflex /ʈʰ/ | ٹھ (two characters) |
| ڀ | Aspirated bilabial /bʰ/ | بھ (two characters) |
| ڃ | Aspirated palatal /dʒʰ/ | جھ (two characters) |
| ڦ | Aspirated labial /pʰ/ | پھ (two characters) |
Sindhi encodes each aspirated consonant as a single Unicode character. Urdu writes the same sounds as two-character sequences. This means a string comparison of the "same" word in Sindhi and transliterated Urdu will not match — they are different character sequences even if they sound similar.
Retroflex Series
Both Sindhi and Urdu have retroflex consonants (sounds made with the tongue curled back). Urdu's retroflex set is: ٹ ڈ ڑ. Sindhi's retroflex set is larger and uses different code points in several cases: ٺ ٽ ڊ ڌ ڍ ڻ ڙ. Some of these are distinct phonemes that Urdu simply does not represent.
The Kaf Problem
One difference that particularly affects digital Sindhi text is the letter for the /k/ sound. Urdu uses ک (U+06A9, ARABIC LETTER KEHEH). Sindhi uses ڪ (U+06AA, ARABIC LETTER SWASH KAF). These look very similar — the difference is a small visual hook — and in many fonts at small sizes they are nearly indistinguishable. But they are different code points.
A large amount of Sindhi text on the internet has been typed using Urdu ک rather than Sindhi ڪ, because Urdu keyboards are more widely available. Searching for a Sindhi word spelt with the correct ڪ will not find documents spelt with Urdu ک, even if they look identical on screen.
U+06AA) for the Sindhi kaf. The Urdu keyboard uses ک (U+06A9). These are intentionally different — selecting the right keyboard matters.
The ۽ Character
Sindhi has one character with no Urdu counterpart at all: ۽ (U+06FD). This is the Sindhi "and" sign — a conjunction mark used in the same way English uses "&" or Urdu uses "اور". It appears frequently in Sindhi prose and is completely absent from Urdu writing. Any Sindhi text that needs this character cannot produce it from a standard Urdu keyboard.
What This Means for Everyday Typing
If you are writing Sindhi and you only have an Urdu keyboard available — whether on a phone, a computer, or an online tool — you face a choice between writing with incorrect characters or not writing at all. The first option is understandable as a workaround, but it accumulates into a large body of Sindhi digital text that is technically mislabelled and unsearchable by correct spellings.
The solution is not complicated. Use a keyboard built specifically for Sindhi — like the one on this site — that maps the correct Sindhi Unicode code points to each key. The characters will look correct, behave correctly in search, render correctly in Sindhi fonts, and remain legible to future readers on any device.
For a deeper look at where these characters come from — why Sindhi needed them and how they were standardised — the history of the Sindhi alphabet is worth reading next.