The mother and daughter were speaking Spanish while walking home from dinner in a Boston neighborhood where more than half of the residents are Latino, and more than half were born in another country.
Suddenly, two women attacked them on the street — punching, kicking and biting them, according to prosecutors and the mother.
The women yelled: “This is America! Speak English!” according to the mother, who asked to be identified only as Ms. Vasquez to protect the identity of her daughter, who is 15, and to prevent her from being harassed.
On Thursday, prosecutors filed felony hate-crime charges against the two women — Jenny Leigh Ennamorati and Stephanie M. Armstrong, both 25 and both of Revere, Mass. — in connection with the Feb. 15 assault in East Boston.
The episode sparked outrage in Boston, a city with a history of racial strife and violence.
“There is no place for hatred or bigotry in Suffolk County,” said Rachael Rollins, the county district attorney. “The sense of entitlement and privilege these defendants must have felt to utter these hateful and racist words, and then to physically attack a mother and her child for laughing and speaking Spanish is outrageous and reprehensible.”
Ms. Vasquez, 46, said on Saturday that she continued to have nightmares about the assault, and that her daughter remained in a neck brace.
“This was terrible — terrible,” said Ms. Vasquez, a South American immigrant who has lived in East Boston for five years. “Nobody expects to be walking down the street and attacked.”
Ms. Ennamorati and Ms. Armstrong are scheduled to appear in court on March 9 on charges that include two felony counts each of violation of constitutional rights with bodily injury, and two misdemeanor counts each of assault and battery.
There was no answer on Saturday at phone numbers listed for either of the women, and it was not immediately clear if they had lawyers.
Prosectors said both women told the police they had been drinking. A police report indicated that Ms. Ennamorati and Ms. Armstrong believed that Ms. Vasquez and her daughter had been making fun of them in Spanish, which they could not understand.
Ms. Ennamorati and Ms. Armstrong began shouting at the mother and daughter before attacking them, the report states.
A lawyer for Ms. Vasquez, Iván Espinoza-Madrigal, said that law enforcement officials filed charges only after the two of them held a news conference on Monday to draw attention to the case.
Mr. Espinoza-Madrigal said Ms. Vasquez had spoken to the police on the night of the attack, but then sought his legal help because she was frustrated with the slow response.
“Based on the details outlined in the initial police report that was done at the site of the incident, this should have been immediately flagged as a hate crime,” said Mr. Espinoza-Madrigal, the executive director of Lawyers for Civil Rights, a nonprofit based in Boston that fights discrimination on behalf of people of color and immigrants.
“The fact that it wasn’t raises serious questions about the process that law enforcement is using to identify hate crimes and resolve them,” he continued.
Mr. Espinoza-Madrigal said that after the news conference, his office heard from other Latino victims who had experienced racial violence in East Boston, and who said that their cases were not being properly investigated by the police.
East Boston’s foreign-born population has risen to more than 50 percent over the past several decades, and its Latino population has increased to 58 percent in 2015 from 1 percent in 1970, city data show.
“This family’s experience was not an isolated event,” said Janelle Dempsey, another lawyer from Lawyers for Civil Rights. “Acts of racism and xenophobia are alarmingly common in East Boston.”
Sgt. Detective John Boyle, a Boston Police spokesman, said on Saturday that investigators had responded to the attack on Ms. Vasquez and her daughter on the night that it happened.
“We referred this case to our own civil rights unit, which actively worked the investigation right away,” he said.
Mr. Boyle added that residents in heavily immigrant neighborhoods like East Boston should report crimes, regardless of their immigration status. Boston is a so-called sanctuary city that limits the ability of local law enforcement to cooperate in handing over immigrants for deportation to the federal authorities.
“If they are undocumented, we will treat them as a victim and nothing else,” Sergeant Boyle said. “No one should be afraid to come to the police if they are a victim of a crime.”
Mr. Espinoza-Madrigal said the attack, which happened at about 8 p.m. near a train station, was captured on surveillance video from a nearby business.
The video shows a woman pointing and appearing to yell before punching another woman. Several people standing nearby also appear to be pushing and shoving one another before police officers arrived. Ms. Rollins, the district attorney, said several bystanders also stepped in to help.
Ms. Vasquez said that despite being badly shaken by the assault, she hoped the charges would encourage other immigrants, even if they are undocumented, to report crimes to the police.
“No one,” she said, “has the right to attack us.”