re: I prefer the spelling "grey" over "gray" - don't know why, I just do.

maybe for the same reason you are likely to spell color as colour?

grey is a word i must have learned very early in life, since i use the english english spelling over the american english spelling.

Yet, i don't really remember being able to read before i went to school (i knew my alphabet, and words (stop, and one way and other 'words' i commonly encountered) but i don't remember 'reading'. maybe i learned grey (where?) along with a handful of the words i learned by sight at preschool age.