Recording speech poses no particular problems, but retrieval of spoken content using spoken queries is presently available only for the approximately two dozen languages in which there is an established path to market; English, German, or Chinese, for example.
many of the mobile-only users who could benefit most from such systems speak only one of the several hundred other languages that each have at least a million speakers; 1 Balochi, Mossi or Quechua, for example.