Dummies can have a direct adverse affect on your child's speech development, if left is use for too long. The relevant section on the Talk Listen Cuddle (TLC) website gives you all the information you need to know about dummies, including how they can delay your child's speech and advice on how to remove them.

TLC - Dummies

 

Here are some other links that offer more support:

The Sleep Dept. - Ditching the Dummy

BBC CBeebies Parenting - When should babies lose the dummy?