Stammering occurs when normal speech is interrupted by the repetition or extension of certain sounds or words. It is also called stuttering and can range in frequency and intensity from mild to severe. Sometimes, speaking in front of a group or talking on the telephone can aggravate the condition, while singing can reduce stammering, and reading can effect people differently, either reducing, or greatly increasing someone's stammer. Stress can sometimes make it worse. The struggle to speak may be accompanied by physical gestures or movements.

You may typically recognise stammering by a tense struggle to get out words. This makes it different from the normal non-fluency that everyone experiences which includes hesitations and repetitions. Commonly it involves the repeating or prolonging sounds of words or the words getting stuck without any sound coming out this is called silent blocking. It is common for people to add extra sounds or words, or outright replace words to avoid sounds that they find hard.

Studies suggest around 1 in 20 young children go through a phase of stammering.

Around four in five children who stammer will grow out of it, although it's difficult to predict when this will happen in a particular child.

It's estimated stammering affects around 1 in 100 adults, with men being around four times more likely to stammer than women.

Sources: Swift Checkup Blog, Stammering.org, NHS.uk.