Vigilo Confido goes the motto of the titular fighting force in Firaxis Studio’s excellent XCOM 2. To any English speaker, even one without any specialized knowledge of Latin, the meaning of the motto appears self-evident. Vigilo—vigil, vigilance, or something to that effect—and confido—obviously, confidence. Or . . . wait, is it confidential? In fact, the Latin is intensely and conspicuously ambiguous. Depending on whether or not those final “o”’s are read as nonal case endings or verb conjugations (to say nothing of the tense), defensible translations of Vigilo Confido include everything from “I Am Watchful; I Am Relied Upon” to…