Hello List members,
I've spent many years working with choirs, and as a result of those
experiences I believe that much "tone deafness" is a matter of
perception (or lack thereof). If I work with a child one-on-one...and
I match his/her pitch, the child usually learns rather quickly to
distinguish when our tones are the same. Initially, the child often
slides down to a lower pitch...to "match" his/her usual perception of
what singing with others should be. This "method" of matching has
rarely failed...in one such case the child had a very unusual
"whispery" speaking voice. Occasionally, a learning disability might
impede learning to match pitches and sing in tune, and reading readiness
is also a factor.
P.S. As an aside, my extended family has fun singing "Happy Birthday"
atrociously, the more musically-inclined singing in keys separated by
1/2 step throughout...causing listeners to marvel that anyone in the
group is a musician by profession.