And that is why the English-speaking countries need to stay out of the development of the new phonetic alphabet. Let the international community decide the “proper” way to pronounce English words.
Slovak was not a written language for many centuries. And it is also a language that has many dialects. When the Slovaks finally got permission (from their overlords) to develop their own alphabet, they had to choose one dialect. They settled on the dialect of Zvolen, in south-central Slovakia. All written Slovak is based on that dialect, and all Slovaks have no trouble working with it.
But even to this day, the regional dialects are still there in spoken form. Some say that all Slovak dialects are slowly being transformed to the Zvolen dialect, but it seems to be a long process. Even in these days of mass media, which usually works with the Zvolen dialect.