Why are thereand?

In the old days, andwere different sounds. was for the sound [o] andwas for the sound [wo]. In the chart, wa line used to be [wa],[wi],[u],[we],[wo]. As you know, in the chart the same line share a common consonant. This is whyis still in the same line with [wa]. At later stage[wi],[we] and[wo] sound changed into [i], [e] and [wo]. As there was no good reason to keep these letters, they decided to stop usingand, but they have kept[wo] for the special use. So what is the special use? is used for a grammatical structure. In Japanese language, cases are marked by particles, which is written by Kana. is used as a partcile, which is to mark an object. Other than the object marker, the sound [o] is always spellt by. Just in case, let me add that I am talking above withing the modernised Japanese spelling system. If you learn classical Japanese in the future, the spelling system is completely different..