I have a speech impediment called Cluttering that makes this issue happen almost every time I speak :/
Sucks having to practice saying a sentence multiple times in my head to make sure I can accurately pronounce each syllable without slurring.
If anyone here has jerky/irregular speaking where it comes off as disorganized or rapid then you might have the same issue I do. Even though you can picture the exact words you need to say, you'll end up combining syllables together or have pauses during speaking where it sounds like you don't know what to say next.