I've had trouble with the TH sound in the past, but that's because in my first language, TH doesn't exist. I've also a little trouble with the 'R' sound in the past, so I used to say 'three' as 'swee'.
Other than that, I never had problems with pronouncing syllables, but I talk softly, pause a lot when I'm speaking, and often get words jumbled up as they come out. Often when I'm saying a sentence, I'll repeat parts of my sentence to correct the jumbled words. I also have this thing where sometimes I have to repeat the first word of my sentence three times before I get on with the rest of my sentence.
It's not because I talk too quickly — in fact, I've had people comment about how slowly I speak. The funny thing is, my parents say that I was an extremely early talker.
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Life ... that's what leaves the mess. Mad people everywhere.