I thought some languages had sounds that didn't exist in others, which leads to a kind of audio colour blindness where you literally can't tell the difference b

I thought some languages had sounds that didn't exist in others, which leads to a kind of audio colour blindness where you literally can't tell the difference between two sounds? Japanese R Vs L is maybe the canonical example. Maybe you can train around this, but maybe you can't. Wikipedia cites conflicting evidence: https://en.wikipedia.org/wiki/Perception_of_English_/r/_and_/l/_by_Japanese_speakers https://en.wikipedia.org/wiki/Perception_of_English_/r/_and_...