Hi ADHD Friend There is a treatment for those who get anxious talking.
In my last life, I was working as a Speech Pathologist.
People that stuttered also have difficulty on the phone.
It is due to Anxiety.
Here are some information and links that I hope help you
When do you feel the anxiety of talking?
Some say the minute the phone rings?
Treatment that focuses on the Anxiety is critical.
Most everyone I know with ADHD has some form of Anxiety.
The trick is to determine the type of anxiety and treatment that best fits you.
I hope this helps http://marc.ucla.edu/mindful-meditations