Senior faculty who are introverts and have problems with communication skills are the hardest group to help. They don’t always see the necessity for improvement and are stubborn about making a change at this point in their career. The sad part is that these folks make themselves, and their lab, department and the whole university look bad to the outside world. The universities should see this as a branding issue and offer support.
Hiring an executive coach is a good choice…with the caveat that it doesn’t sustain improvement after the coaching session(s) is done.
What I’m hearing now is that Toastmasters is one of the best ways for lifelong learning, practicing and teaching speaking skills. Particularly appealing (from my point of view) is that Toastmasters is 1) inexpensive, 2) self-paced, 3) well-resourced, and 3) a safe place to practice new skills. The new TM Pathways program is online too, enabling members to watch tutorials, read articles and discover new techniques for speaking. There are many TM clubs within a 5 mi radius of most towns. More info available at: https://www.toastmasters.org.
In addition to improving public speaking, training in assertiveness, leadership, and interpersonal skills might help these folks. Such training may be available from the university human resources department
Stress reduction classes might be useful. (Badly needed for all of us following the last election.)