In May, Latino protesters at a rally in Los Angeles failed to heed warnings to disperse—warnings shouted at them in English from a noisy police helicopter. Hundreds were injured in the ensuing melee, which might have been prevented by the Phraselator, a handheld device that can translate 100,000 words or phrases, including crowd control messages like "We need you to move away." Created by Voxtec of Maryland, the Phraselator was designed for American cities where immigration is booming. Priced from $2,500, the device is cheaper than translators, but less effective because it works one way, like a bullhorn.Still, applications are spreading. In Lee County, Fla., corrections officers use the device to ask Spanish- and Creole-speaking prisoners yes-or-no booking questions. Rescue services are considering using the device in earthquakes, floods and wildfires. And in Los Angeles, police are programming Phraselators to translate into Mandarin Chinese, Korean, Japanese and, of course, Spanish.