I spent so many time almost screaming in the noisy environment that is, the bar I work in (for the time being) that I started to whisper once on vacations. The consequence of this is that I started to speak to high for range and to misuse my voice, which eventually damaged my singing voice.
Your speaking voice influences your speaking voice.
I’ve had problems with my speech since mid-school, there my schoolmate would listen to all my jokes but never to what I was thinking. I really had a short window for delivering fast everything I had to say, so I started to speak really fast and would trip on each word, since the attention span of my audience was so short I had to find the exact word each time if I wanted to accurately express what I had in mind (that was a long sentence).
After learning how to sing I had to relearn how to speak.
Which was my salvation I could finally regain my eloquence without jeopardizing my singing voice in any way. And there is a certain satisfaction in speaking exactly the way you think you speak (if it makes sense) I can express loud (or loud enough) what I have in mind in the tangible sonic world which is ours (I’m use a lot “which” today).
I guess not being able to express what I wanted pushed me towards becoming a full-time songwriter after being a bass player. Expressing my thoughts through songs I created and actually singing my thoughts was one of my first motives for songwriting. I realize 10 years down the line.
I don’t really acticulate when I speak (well I plain don’t articulate) but I’m ready to exaggerate when I sing, isn’t it revealing.
To sum up, your speech is really important, you way find ways to express yourself without expressing yourself, however they will still be a time when you will have to have your voice heard. Take the time to solve your problem, to trace back when you’ve started to have issues with your speak.
Reach out for help, take care of yourself and heal yourself.