Because then you could never encode real works of literature that use esoteric or non-standard grammar. Good luck encoding Huckleberry Finn with your system. O

Because then you could never encode real works of literature that use esoteric or non-standard grammar. Good luck encoding Huckleberry Finn with your system. On the other hand, encoding smaller units reliably (phonemes, graphemes, whatever is appropriate) and using compression over top of that usually gets you really close to what you wanted, but with greater expressiveness. English text compresses really fantastically well, so why overthink it?