What is a good age to take away the pacifier?

I was wondering because my little cousin is almost two years old and she still has a pacifier and her mouth looks like the people of whoville. her mom just pops it in her mouth every time she starts to cry. and she wont talk because its in her mouth all of the time the only word that she can say is doggie. and then she sometimes mumbles. i have a cousin that's not even a year old that is speaking clearer than the almost two year old.