1. A speech intelligibility testing system, comprising: a sound device for producing a plurality of stimulus words to be heard by a test subject, each of said plurality of stimulus words comprising a plurality of speech sounds; a display means, configured to display to said test subject a set of selectable word pairs corresponding to a set of contrasting speech sounds whenever a stimulus word is provided to said test subject, each of said words comprising a real word with a high degree of familiarity, a first word of said word pair corresponding to said stimulus word and a second word of said word pair differing from said first word by at least one of said set of contrasting speech sounds; and means for said test subject to select one word of said word pair upon deciding which one of said two words was heard.