“Sometimes officers will get a very brief exposure to interacting with people with different disabilities, including hearing impairments,” Stoughton told me via email. But “it’s not something they spend much time learning about.”

This deficit can exacerbate situations where police are already prone to using force. Even if an officer has learned when to use it—and when to hold back—they may not know how to apply those lessons to interactions with deaf people.

What’s more, a one-off session “really doesn’t help unless there’s a reiteration of the training,” said Matthew Dietz, litigation director of the Miami-based Disability Independence Group. Since 2005, uniformed officers in the Miami-Dade Police Department have completed a 40-hour crisis intervention training program, but a department representative told me it doesn’t include instruction on deaf and hard-of-hearing issues. Dietz, who handles cases of police discrimination, said that, like the police Engelman observed, “officers are really not aware of the fact that they’re supposed to get interpreters.”

Eve Hill, the former director of the Justice Department’s Disability Rights Division, noted that deafness is a low-incidence disability. “Police are doing training and then not having an interaction with a deaf person while they remember the training,” Hill said. “People forget.”

Cost can also be a barrier to departments’ ADA compliance. The law’s effective-communication and reasonable-accommodation clauses are unfunded mandates; public and private entities use their own money to fulfill them. “There remain many departments without any real resources to back up their policies, so interpreters and translation equipment aren’t always available,” said Vitale, who also directs the Policing and Social Justice Project at Brooklyn College.

Nonetheless, advocates are skeptical price is a serious factor. “Many terrible incidents happen in departments that have resources, but the officers involved never bothered to access them, even when requested to do so by the deaf person,” Vitale said. “Of course cost is an issue, but often it’s lack of concern or awareness by an officer.”

That’s allegedly the case in Austin, Texas, where the police department contracts with two interpreting agencies, one for business hours and one for nighttime. Amber Farrelly, a criminal-defense attorney in the city who represents deaf clients, alleged officers don’t use them: “I watch these dash-cam tapes all the time. Ninety-eight percent of the time, there’s no interpreter ever called,” Farrelly said. “The thing that just kills me is that they have this already. They have the contract.” (The Austin Police Department did not respond to requests for comment.)

The Justice Department has investigated dozens of police departments for their ADA compliance, often culminating in settlements where cities agree to adopt new policies and practices for interactions with deaf and hard-of-hearing people. “We’ve been seeing steadily problematic interactions between the police and deaf people,” Hill explained.