For him, its' like hearing a piece of music and then looking down at the black and white keys of a piano, not knowing how each note corresponds to the identical-looking keys before you.

One way of understanding this is to imagine that you are traveling with a speaker of such a language and staying in a large chain-style hotel, with corridor upon corridor of identical-looking doors.

I've been looking at what self-proclaimed experts were saying about unemployment during the Great Depression; it was almost identical to what Very Serious People are saying now.