IAAY (Institute for the Academic Advancement of Youth) was a name used by CTY in the 1990s to describe the organization as a whole, encompassing CTY, CAA, Study of Exceptional Talent (SET), etc. The acronym was emblazoned on shirts and lanyards. Eventually wiser heads realized that good old "CTY" is a better recognized name, and reverted back to that.
Students who attended CTY during the IAAY days tended to pronounce "IAAY" as "Eeee-ahhhh-eeee."
See also: CTY organization history.