Someone told me that the proper way to pronounce the ‘sof’ (last letter of the aleph-bais) is ‘th’. Should I daven and say brochos using this pronounciation? (note: I am Ashkenazi and so is the person who told me about the ‘sof’ being ‘thoff’)
Better not to change from what you have been doing till now. We don’t have solid evidence of what it was originally.