Re: NVDA speaks all punctuations except period
Make sure that no entries have been made in any one of the dictionaries (most likely the default dictionary, but check them all) that would prevent a period from being spoken.
Also check in Punctuation & Symbols settings (NVDA+N,P,P), to be certain that the single period stand-alone, and at the end of a sentence, have not been tweaked to have a blank replacement text. If your Punctuation & Symbols settings are still in their default state, or something near to it, typing the word "dot," in the Filter by edit box should pull up both the sentence ending and standalone periods with a replacement text of dot. If it doesn't, then something's been changed, and it's impossible to say what without seeing it/having direct access to it.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Science has become just another voice in the room; it has lost its platform. Now, you simply declare your own truth.
~ Dr. Paul A. Offit, in New York Times article, How Anti-Vaccine Sentiment Took Hold in the United States, September 23, 2019