I am a chronic mumbler. I don’t know how to fix it either and it seems to be getting worse as the years go by. I think about it a lot and I think it partly came about from being embarassed about my Northern Irish accent when I lived in Birmingham for a few years as well as not being able to modulate my voice correctly when I speak. I constantly think I’m speaking at an acceptable volume and to my ear, it does sound like the same volume as everybody else but everyone struggles to hear what I’m saying. I’m not confident in being able to speak louder without it coming across as shouting.
I don’t really know how to sort the problem, it drives my TV mad and I notice people in work struggling to make me out or asking me to repeat myself a lot. I dont really have the time or money for speech therapy either… if it’s even available for adults