From today's NY Times, lexical-gustatories are individuals who "involuntarily 'taste' words when they hear them, or even try to recall them." According to Dr. Julia Simner, a cognitive neuropsychologist and synaesthesia expert from the University of Edinburgh, lexical-gustatory synaesthesia is an extremely rare disorder. Only 10 lexical-gustatories indentified in the US and Europe.
A summary of Synaesthesia: The taste of words on the tip of the tongue, a report by Julia Simner and Jamie Ward, can be found online at Nature.
For more info, download the following articles on lexical-gustatory synaesthesia here:
Ward, Jamie, Julia Simner, and Vivian Auyeung. 2005. “A comparison of lexical-gustatory and grapheme-colour synaesthesia. Cognitive Neuropsychology; vol. 22(1): 28-41.
Ward, Jamie, and Julia Simner. 2003. “Lexical-gustatory synaesthesia: linguistic and conceptual factors.” Cognition; vol. 89: 237-261.