MALDEN — Police Officer Keith Wilson was in the middle of his shift one recent day when his radio crackled with an alert. A woman had disappeared.
He rushed to the house on Clifton Street, where he discovered the woman's worried husband, her sister-in-law, and an increasingly common problem in this immigrant city: They were speaking a language the officer did not understand.
In the past, Wilson might have muddled through with gestures, asked a neighbor to translate, or waited for an official government translator to show up. But this time, Wilson called his sergeant to bring him "the box," a handheld mobile device the size of a garage-door opener, which, with the press of its single button, links authorities to live translators in less than a minute — wherever the officer happens to be.
"I was just hoping that the box would hurry up and get there," Wilson said of the incident, which happened last month. "They're talking to me like I understand, but clearly, I don't understand."
Malden, a city of 60,000 with the second-highest percentage of immigrants in the state, nearly 40 percent, is among dozens of municipalities and agencies nationwide using the new devices to overcome language barriers that can hinder investigations and delay response times. While hospitals and 911 operators have quick access to translation services, city officials say police and other emergency responders in the field did not.
Residents in this once mostly white city now speak more than 50 languages as distinct as Hindi, Mandarin, and Yoruba.
Nationwide, more than 130 municipalities, school departments, and even an area-rug factory in rural Alabama have started using the devices since the Minnesota-based company, RTT Mobile Interpretation, started distributing them in February, said John Grove, who owns the US distribution rights.
Grove said the device allows officers and others in remote locations to tap into the longstanding translation services familiar in hospitals and courtrooms.
He said the company links to US-based translators in 180 languages and records the calls, providing audio recordings and transcripts upon request.
In Massachusetts, Salem police are also using the device, and the Attorney General's office borrowed them for a human-trafficking investigation that led to indictments in June.
Advocates who say police should hire more officers who speak other languages are pleased. But the service comes with a cost: Even those who like the device say it can be pricey — $20 per unit each month and then $1.50 to $2 a minute per call.
Steve Kropper, cochairman of Massachusetts Citizens for Immigration Reform, which advocates for limits on immigration, said the growing need for translators is one of the "hidden costs" of immigration and said he thought the city should find a cheaper service. Still, he said, offering translators seemed like a "sensitive and good thing to do."
"We want our police to be able to speak to a broad range of visitors, whether they're legal or illegal," he said.
Company officials say bulk prices are available and Malden officials suspect they are saving money because the device helps them answer calls quickly. And, city officials say, they could never hire enough bilingual staffers in a city as diverse as theirs.
Over the past two decades, the white population in Malden has plunged, and the triple deckers and Victorians have filled with immigrants seeking much the same things as their predecessors, including good schools and affordable housing. The largest immigrant group is from China; Malden's number of immigrants from the country soared from less than 300 in 1980 to more than 6,000 in 2011 census estimates. Malden is also home to sizable numbers of people from Haiti, India, Brazil, and Vietnam.
"These are just functional things we have to deal with," said Ron Cochran, director of city communications. "We want to serve businesses and residents efficiently. We want people to be happy to live here."
Cochran said the city paid for the devices with a federal grant and is testing them for the next year, stationing devices in the fire and police department, schools, the mayor's office, health and building inspections. The police, for instance, have two devices, one in the department and another in a roving patrol car.
One day this month, a couple visiting from China approached the Malden Fire Department; the woman spoke in high worried tones the firefighters did not understand. A firefighter sent for the box and pressed the button.
After a short delay, a voice came over the box's speaker.
"My name is Joe," the translator said, according to a copy of the recording provided to the Globe. "What language do you need, please?"
"We believe it's Chinese," the firefighter said in a thick Boston accent.
It was Mandarin. The translator relayed that the man had a painful rash and chills. They had travel insurance, but feared they couldn't afford an ambulance. They had just $25 in lunch money.
The firefighter told the woman the insurance should cover the cost and said an ambulance was on its way.
Police and company officials said the mobile device also helps officers investigate crimes. Last year, for instance, several immigrants called Malden police to report that they had been assaulted while walking home from the T, but they could not communicate well enough in English to give police a good description of the suspect, who fled.
And, they say, using neighbors or friends to translate is risky, because they might not translate the information accurately or they might be involved in an alleged crime
On an afternoon in July, Officer Wilson confronted these challenges on Clifton Street, where the woman was reported missing. He said the translator explained that the wife and her husband were splitting up. She had left the house after an argument and never returned, so he called the police.
Wilson said the reception on the device was sometimes spotty and using a translator can be awkward. But, he found the man's wife, verified that she was safe and closed the case.
"You want to try to get all the information up front," he said. "It's just really hard to do that with that language barrier there."
At the senior center downtown, several immigrants said they felt relieved a few weeks ago when police Chief Kevin Molis, the mayor, and others unveiled the device to the public.
"We feel safer," said Feng Zhi Li, 60, who came to the United States almost a year ago from Beijing, taking a break from a ping pong game.
Peiyu "Peggy" Luo, a 63-year-old immigrant from China who came to America in 1990 and speaks English, said even long-term immigrants might revert to their native language in an emergency.
"This is very important," said Luo. "When people get in an emergency like a . . . " She paused and glanced at a translator, suddenly unable to recall the words for "heart attack."