> All the letter (and sounds) used NEED to be pronounced, the same way, for native speakers of English, French, Russian, Spanish, and also various major (eastern) Asian languages. That means that when an otherwise uneducated (in languages/reading the squiggly version of words from a dictionary) user in one of those languages tries to read one of the words it should sound like only a slight accent, not a major flub.

This constraint effectively removes vowels from your phonetic inventory.