How many letters are there in the alphabet? More than 26, but it depends on the language and usages of the language, and the stage of that language. We are a bit beyond the age of the typewriter and the restrictions it places on what letters can be produced, and we deal every day with multiple linguistic standards, in prose, in quotations and in names of people and places.
We must be able to do justice to the variety of the world and even of our own country. Computers are capable, but are the systems built on them?
With this in mind, I wrote a couple of on-line papers, which I will continue to refine: