I've struggled with putting my thoughts into words almost my whole life. Only in the last 2-3 years I started to actually get better (I'm 28 soon).
What could help is
- If you managed to find words for a thought write them down somewhere (I used phone notes for this)
- Not sure about this one, but maybe reading books out loud might help (doesn't have to be with anyone present)
I did both of these occasionally, but I think what actually helped me here was LSD, which I don't recommend unless you've properly researched the (side-) effects, are aware of all the risks and have trusted source to get it from.