I don't know if anyone else has this problem but I have a really pacific issue. In general just I suck at talking. I find it hard to put my thoughts to words, I never know what words to use and I never know what to say.
I talk like xQc irl and the act of using words to hard I'm always slurring them out even tho I try not to and I have a stutter and a slip so saying thing is very hard.
Practice by reading out loud slowly and enunciating like you want a child to understand you. Do the same with others' speeches, as they were written to be said out loud. If they are recorded in an accent that is in the neighborhood of your goal, even better - you can practice talking exactly like a recording.
Even though this isn't off-the-cuff speaking, you will likely adopt verbal patterns that let your words flow more freely.
You can also join clubs that are dedicated to speaking to other people. If all else fails, something like toastmasters, though that's specifically about public speaking.
If this doesn't go well, that's also okay. You might want to look into a speech therapist if practice doesn't help.