The answer partly depends on whether we are talking about the sounds or letters of vowels and consonants. By mentioning “alphabetic languages”, the questioner is presumably asking why most versions of ...

Most three-year-olds can count, some may know the alphabet and the words to their favourite song. But it is a rare occurrence when a three-year-old child knows their times tables, the Greek alphabet ...

The number has not been consistent throughout its existence. Russians use an alphabet based on the Cyrillic script. The modern Russian alphabet has 33 letters: 21 consonants, ten vowels and two signs.