What are the causes?
We don't really know yet. Scientists have been working for years to try and find out whether there is a cause and whether there is a cure. So far all that has been agreed is that the problem is highly complicated.
It probably isn't caused by one single thing. It's more likely that it is the result of a combination of things. More importantly the "ingredients" of stammering are probably different for every person who has a stammer and that the things that help stammering may be slightly different for everyone too.
Different factors may be impacting on the stammering:
Family history of stammering in blood relatives
The organisation of the brain for speaking
The co-ordination of the speech mechanism
These are all probably inter-related.
Speech and language development
There seems to be some link between the way in which a child develops speech and language which is important. This may either be that a child is quicker or slower than his age group, or that there were some earlier, sometimes quite subtle, difficulties
There may still be some minor, often unrecognised, difficulties. An example would be in 'word retrieval' or 'word finding' - here the filing system for vocabulary is not very efficient. It's the 'tip of the tongue' phenomenon! The person knows exactly what they want to say but the exact word they want to use escapes them for a second or two
The person's instinctive or natural rate of talking also may be influential
Environment - past and present
Rapid pace of life - lots of commitments, activities and demands
Everyone speaking quickly
Everyone talking at once
Expectation to speak up - whenever
Personality - the sort of person you are can make a difference
Perfectionist (or self-critical)
Each person has a different set of factors that makes them vulnerable to stammering in the first place. But perhaps it is now more important to consider what is keeping it going.What happens?