Sukoon and shaddah are the two marks that tell you what to do when a letter carries no vowel of its own. Sukoon (stillness) means the letter is pronounced without any vowel and joins straight onto the letter before it; shaddah (strengthening) means the letter is read twice, first still and then with the vowel written on it. Both are simple to describe and both cause a surprising share of the errors teachers hear, because the mouth badly wants to add a vowel where there is none.
Sukoon: a letter with no vowel at all
Every consonant you met in the early rows of a Qaida (a graded primer for letters and vowels) carried a fathah, kasrah or dammah. A letter with sukoon carries none. It is a consonant and nothing more: the tongue or lips make the letter's shape, the sound is released or held as that letter requires, and no vowel follows.
The difficulty is that English speakers rarely say a bare consonant in the middle of a word without a tiny vowel slipping in after it. Asked to read a word like "ab", a beginner will often produce "aba" or "abu". That slipped-in vowel is the single most common sukoon error, and it creates a syllable the text does not contain. If the short vowels themselves are still new, read our beginner's guide to the Arabic harakat first, because sukoon is defined by their absence.
What sukoon looks like, and how the still letter joins the one before
In the mushaf (a printed copy of the Quran) sukoon is written as a small sign above the letter. In many editions it is a small circle; in others it is a shape like the head of the letter خ; editions printed in South Asia often use a small crescent. The shape varies between printings and the meaning does not: this letter has no vowel.
The reading rule is that a sakin letter (one carrying sukoon) is not read alone. It attaches to the vowelled letter before it and the two are read as one closed syllable. So ب with fathah followed by ر with sukoon is not "ba" then "r" but "bar" in one movement, the ر closing the syllable. Practise by reading the vowelled letter and, without any gap or any new vowel, adding the still letter to its end.
Some letters are released when sakin and some are held: a sakin م or ن carries its nasal resonance, and a sakin س hisses until you stop it. Let each letter behave as it does; the only thing forbidden is a vowel.
Shaddah: one letter written, two letters read
Shaddah is written once but read as a doubled letter. The first of the pair is sakin and the second carries the vowel. So a ب with shaddah and fathah is read "b-ba": the lips close for the first ب and stay closed for a moment, then release into the second ب with its fathah. The word rabbi shows it clearly: rab, then bi, with the closure held between them.
Two things follow. A shaddah always contains a sukoon, so everything above about not adding a vowel applies to its first half. And the doubled letter takes longer to say than a single one, because of the hold in the middle; that hold is what beginners most often leave out.
How shaddah appears in the mushaf
The shaddah is a small sign shaped like a tiny "w" placed above the letter. The vowel of the second half is written with it: a fathah or dammah sits above the shaddah, and a kasrah is written either directly beneath the shaddah or below the letter itself, depending on the edition. In every case the vowel belongs to the second, released half of the doubled letter, never to the first.
Words such as inna and thumma, which occur throughout the Quran, show the pattern plainly: vowelled letter, held first half, released second half. They make excellent early practice.
The errors teachers hear most
- Swallowing the sakin letter. The still letter is so short that beginners sometimes skip it, so that "bar" becomes "ba". Every letter in the text is read.
- Adding a vowel after sukoon. The opposite error: "bar" becomes "bara". Record yourself at slow speed and listen for an extra syllable.
- Under-holding the shaddah. The doubled letter is read as a single letter with a vowel, so rabbi sounds like rabi. The word changes.
- Putting the vowel on the wrong half. Some learners voice the first half of a shaddah and leave the second bare. The first half is always still; the second always carries the mark.
- Breaking the join. Pausing between a vowelled letter and the sakin letter that closes its syllable turns one syllable into two. The join should be seamless.
A short practice progression
- Read a row of two-letter units, each a vowelled letter followed by a sakin letter, slowly, listening for any extra vowel at the end.
- Read the same units with the sakin letter changed each time, so the mouth learns to hold or release according to the letter.
- Read a row of letters carrying shaddah with fathah, then with kasrah, then with dammah, holding the first half deliberately long before releasing.
- Read short words that mix all three: a vowelled letter, a sakin letter, a doubled letter. Words from Surah Al-Fatihah and the short surahs at the end of the mushaf provide plenty.
- Return to normal pace and check that the holds and joins survive.
Rule of thumb: when in doubt, hold the shaddah a little longer and the sukoon a little tighter; the common error is always too little, not too much.
A teacher on the Noorani Qaida course hears within a row whether the sukoon is clean and the shaddah held; this is the stage where a live ear pays for itself.
Where sukoon and shaddah lead in Tajweed
Once a still letter is secure, the rules of Tajweed begin to describe what particular still letters do: five of them bounce slightly when sakin, which is the rule of qalqalah, and a sakin ن changes its reading according to the letter that follows, which is the subject of the noon sakinah and tanween rules. A shaddah on ن or م carries a nasal resonance of its own, explained in our guide to ghunnah. None of those rules can be applied until plain sukoon and shaddah are read correctly. All of this assumes the reading of Hafs from 'Asim; other transmitted readings differ in some details.
Frequently asked questions
Is a letter with sukoon silent?
No. It is pronounced fully; it simply has no vowel after it. A silent letter would not be read at all, and most editions of the mushaf mark that case differently. A sakin letter is heard as the close of a syllable rather than the start of one.
How long should I hold a shaddah?
Long enough that the letter is clearly heard twice, and no longer. There is no fixed count; copy a reliable reciter and let your teacher adjust it. Beginners almost always hold it too briefly.
Why do some letters with sukoon sound as if they bounce?
Because five particular letters have a slight echo when still, a quality called qalqalah. It is a property of those letters, not a change to the sukoon itself, and a teacher will introduce it once your plain sukoon is secure.
Can a word begin with a sakin letter?
No. In Arabic a word never starts with a still letter; the first letter always carries a vowel. This is why a sakin letter always has a vowelled letter before it to attach to.
Do sukoon and shaddah appear in ordinary Arabic text?
Ordinary printed Arabic usually omits them along with the short vowels, leaving the reader to supply them from knowledge of the word. The mushaf writes them all, which is why beginners can read the Quran precisely long before a newspaper.
What is the difference between sukoon and a long vowel?
A long vowel stretches the vowel sound; sukoon removes it. The letters alif, waw and yaa can lengthen a preceding vowel and in that role carry no mark, which beginners sometimes confuse with sukoon. The rules of lengthening are treated in our explanation of madd.
Read a row of still and doubled letters to a teacher
The two errors that matter most here, a slipped-in vowel and a shaddah cut short, are exactly the ones a learner cannot hear in their own reading. On our Noorani Qaida course, a teacher listens to each row one-to-one on a private video call and corrects the hold and the join in the same lesson. Book a free one-to-one trial class and bring the word rabbi; ask the teacher to tell you whether your shaddah is being held.
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