My lad, now 14 never had a pacifier, his speech could be awkward but this was due to doing the woman thing and engaging the moth before the brain.
He used to get so frustrated and kick up when people couldn't understand him, had speech therapy as well, till I stopped it a sit made him more frustrated, I simply did a deal with him reading books, and made him think about exactly what he was going to say before he started speaking, and if he did this correctly he'd get a smartie, otherwise I got it!!
Within 1 month he was taking his time talking and getting everything perfect, not talking till he knew exactly what he wanted to say, I think the fact I was getting his smarties helped!
Just a thought, might be worth a try ?
tabetha