I guess I'd mostly agree, Mark -- although I've never met a person who genuinely could not hear tonal differences, I wouldn't think is doesn't exist. Maybe the term "tone deaf" is just overused. Short of some sort of physical brain or ear damage, I would be pretty sure that tone perception is a matter of brain-ear coordination, and not a physical defect in the vast majority of "tone deaf" individuals.

But there are folks who are genuinely color blind, for example, which is a different condition from someone who isn't good at matching colors. The first is a defect of vision, the second is a lack of perceptive training.

The range of abilities between tone deaf and perfect pitch are probably mostly due to training, and not some personal ability -- but then again, some people are just more or less talented in different areas, and all portions of the spectrum may not be obtainable for everyone.

Wouldn't a person who is genuinely tone deaf have difficulty understanding and speaking language?