Police say the attacker was walking by three men who were speaking Cantonese on a street in Bensonhurst Tuesday night.
The group of men, ages 51, 56, and 57, said he made fun of the way they spoke.
The 56-year-old victim confronted him about it and the attacker punched him in the face.
The video then shows the attacker taking out a knife and spraying the victims in the face with an unknown substance.
He then ran off on 20th Avenue.
The three victims were taken to Maimonides Medical Center with minor injuries.
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