a system and method for improving the response time of text - to - speech synthesis utilizes “ triphone contexts ” as the basic unit , instead of performing phoneme - by - phoneme synthesis . the method comprises a method of generating a triphone preselection cost database for use in speech synthesis , the method comprising 1 ) selecting a triphone sequence u 1 - u 2 - u 3 , 2 ) calculating a preselection cost for each 5 - phoneme sequence u a - u 1 - u 2 - u 3 - u b , where u 2 is allowed to match any identically labeled phoneme in a database and the units u a and u b vary over the entire phoneme universe and 3 ) storing a group of the selected triphone sequences exhibiting the lowest costs in a triphone preselection cost database .