Morse code question: when using taps instead of tones how can you tell if the last tap is a da or a dit?

Probably guess. For example, let's say your trying to say HELLO. It'd be .... . .-.. .-.. ---. And instead of the ---, you think it's --. which would be G. So you use common sense. Do you think they are saying HELG? Probably not lol....