Until my social skills improved much in my late thirties and forties, through my own daily efforts, I was very anxious at getting all calls and in calling all others except my brother. They caused me much panic. Fortunately, living on my own for twenty years from age 18 to 38 forced me to get better there, as I had to do things by myself, meaning if I could not talk by phone or one-to-one in acceptable ways, I'd not get my related needs met, and I'd have greater anxiety in the process.
Also, my attitude was: "If I can communicate well through writing, why not through voice too?" Yes, my entire life up to that point was communicating through writing, but I felt some regular practice answering out loud vocally random comments, topics and questions that I heard on the radio, tv, or seen through another's writing to me or to another, as examples, would not take too much time for me to be effective and efficient in my phone communications, and as my motivation was strong to be my best there.
I realize though regardless how effective and efficient others are at communicating by voice with each other, often it is hard anyway to maintain that if the other has interests that are totally different than yours, if reciprocal needs are not being met, and/or if personality styles or certain important values clash. As for me, I am not too picky there, but I have my limits. So, regardless if it is a family member, acquaintance, or other that I talk to, I will act and react as I see fit, based on any good, neutral or concerns I see.
As for talk to business persons and other service professionals, I am always more brief, polite and formal there. I never share personal information to them, as I just want information, the service done, and so on. It does not matter if I am too different than them, as the goal is different.