M-TD (Or Em-Teedee), short for Miniaturized Translation Droid is an expanded universe Star Wars character, specialising in human-Wookie relations.
When Lowbacca the Wookie enrolled in Luke Skywalker's Jedi Academy on Yavin 4, his uncle Chewbacca foresaw a problem, in that few humans can understand, let alone speak the Wookies' language of Shyriiwook. Chewie thus collaborated with C-3PO in building a translator droid so Lowie could make himself understood, Chewie building and engineering the droid, and Threepio programming.
Em-Teedee is small enough to fit into the average human hand, but spends much of his time clipped onto Lowbacca's belt, translating his master's barks and growls. As a mark of his programmer however, Em-Teedee has a tendency to embellish the translations somewhat, in an attempt to make Lowie sound more dignified. He has been dropped on several occasions but survived each time, being extremely durable, and he was later equipped with small hover jets, enabling him to move around freely.