A highly efficient, real-time text-to-speech system deployed on CPUs
Speech Synthesis has always baffled me.  You could run a reasonable (albeit strangely accented) version on 16Mhz Macs without major CPU impact.  The code including sound data was less than a megabyte.In order to achieve modest improvements in dictation we're throwing entire GPU arrays at the problem.  What happened in the middle?  Was there really no room for improvement until we went full AI?