This paper reports a set of studies of some phonetic characteristics of the American English represented in the TIMIT speech database. First we describe generally how we use the non-speech files on the TIMIT CD with a commercial database program. Some studies of pronunciation variation using only the segmental transcriptions and durations of TIMIT are then described. Results of such studies should be useful not only for linguistic phonetics but also for speech recognition lexicons and text-to-speech systems.