Eventually, the Chinese make the decision to attack the aliens, at the same time that Adams’ Lousie Banks begins to understand how the alien language truly works.
Different nations treat the alien visitors with different degrees of suspicion in Arrival.
According to Thrillist, who was there, the line translates to “In war, there are no winners, only widows.”
However, as the line is in Chinese, and not subtitled, we have no idea what is said.