Along with Terrence Kaufman and Lyle Campbell, he helped to define Mesoamerica as a linguistic area.
Smith-Stark worked two summers on Frederic Cassidy's Dictionary of American Regional English project.
[citation needed] He spent 22 months in the Marines working in military intelligence at Cherry Point, North Caroline.
He became an expert in colonial Zapotec and Nahuatl, and he completed studies related to missionary linguistics in early New Spain.
[1] In the Research Library Juan de Córdova (Oaxaca, México) is available the Documentary Collection Thomas C. Smith-Stark.