Ever since Japan opened to the outside world in the middle of the 19th century after some 250 years of isolation imposed and enforced by its ruling shoguns, the Japanese language has been widely regarded as a kind of code.
Foreigners, it is generally conceded, may be able to learn to "decipher" this code, but the deeper meanings of the words — which give voice to the hearts and minds of the Japanese people — are still considered by most Japanese people to be beyond their grasp, just as beautiful stones in the depths of a clear pond cannot be reached by those destined to remain on the edges. Foreigners could stick their toes into the water, perhaps even enter the pond, but they could not reach the depths.
Some Japanese people, I fear, still believe this, but many now see that foreigners can be deep divers too; that barriers to understanding can be breached.