My biggest qualm is a qualm I have with any acronym/abbreviation. If you’re going to introduce a letter that is unknown to many, then define your term. Otherwise, I’m going to assume it’s a typo, or I going to not recognize it.
All acronyms and abbreviations, or at least those that aren’t commonplace, should be defined somewhere adjacent to their use, or else you are excluding people.
Speech/text is only useful if you’re using it in a way that appropriately conveys a message to it’s intended audience.