You’re basically describing the various character encodings which preceded adoption of Unicode. No, UTF-8 doesn’t support that. That’s the sacrifice it was will

You’re basically describing the various character encodings which preceded adoption of Unicode. No, UTF-8 doesn’t support that. That’s the sacrifice it was willing to make, to eliminate the need to distinguish between character encodings: a string isn’t a sequence of bytes. Even if you don’t appreciate that convenience (and the highly standardized, easily abstracted rules of combined bytes), maybe you’ll appreciate that the complexity of supporting multilingual users would mean multipart data, arbitrarily fractured. As in a single text message using multiple character sets could be dozens of payload boundaries. Does that really sound easier or more painless than UTF-8’s variable-length code points?