> the idea that a natural language could actually be designed was a shock to me
Perhaps the Japanese grammar was designed by a small group of individuals, maybe even one individual, a long time ago, and promoted officially by the Japanese Emperor of the time. Many writing systems have been designed from scratch in the past. Many spoken languages have risen from regional dialect to imperial language, and at least one language, Israeli, was brought to life after being dead as a spoken language for centuries. No-one's ever found a definitive link between Japanese and any other language. Perhaps at some time, the Japanese grammar was designed from scratch, perhaps using a mixture of vocabulary from many other nearby languages existing at that time, and promulgated to become the language of all Japan.
Perhaps the Japanese grammar was designed by a small group of individuals, maybe even one individual, a long time ago, and promoted officially by the Japanese Emperor of the time. Many writing systems have been designed from scratch in the past. Many spoken languages have risen from regional dialect to imperial language, and at least one language, Israeli, was brought to life after being dead as a spoken language for centuries. No-one's ever found a definitive link between Japanese and any other language. Perhaps at some time, the Japanese grammar was designed from scratch, perhaps using a mixture of vocabulary from many other nearby languages existing at that time, and promulgated to become the language of all Japan.