Among other reasons, while there are 52 symbols to learn (ignoring punctuation, numbers, and other fun esoterica), you could substitute lowercase and uppercase

Among other reasons, while there are 52 symbols to learn (ignoring punctuation, numbers, and other fun esoterica), you could substitute lowercase and uppercase letters for each other without losing or changing the meaning of the word - so while there are 52 symbols, they map to only 26 letters, with contextual rules about which symbol is used for which case. More pragmatically, I'd express it as "using any mix of uppercase or lowercase letters wouldn't obscure or change the word being expressed". (I'm sure there are exceptions where you could conflate a proper noun with another noun without proper capitalization, but since you don't get capitalization in speech, people generally can deal with it.) e: Thinking slightly more, I'd probably phrase it as "52 symbols map to 26 letters, and the words of the language are defined in terms of letters."