I have seen children whose ability to speak clearly was greatly effected by
pacifiers.  My son, who plays with one of these children daily, comes home
saying things like "Schlocate" "bend" (friend) and other great versions of
the English language.  This is very frustrating in a bi-lingual environment
where it's difficult enough to teach the kids to speak English properly.
Parents need to be informed of speech impediments caused by pacifiers, too.
In fact, this was one great reason the Mother of the child herself gave the
kid in order to convince him to give it up (He's 4!)  She said "You have
such a sweet voice and when you have the dummy in your mouth I can't
understand all the important things you have to say"..  I hope she'll
remember it next time.

The speech therapist has mentioned that the kid does have good mouth
structure (he was nursed), and should get over the problems soon.

Nofia