Have you not seen this monster ' s movepool ? <| sep |> This is like people who think its brass tax or intensive purposes <| sep |> That ' s a possibility , and I ' ve seen others suggest that because they didn ' t speak to each other for 2 years and probably rarely spoke in the 2 months after Kirito woke from SAO that they might still not be used to the sound of each other ' s voices . Also since they ' re both still in adolescence , their voices might sound different than how they remembered them . Based on what he told Silica , Kirito might still think of his sister as a loli . Personally I ' ve never had trouble recognizing the voices of immediate family members , regardless of whether or not I expected to hear them , could see them , or haven ' t heard their voice for months , even when their voice was distorted via technology . If anything , not expecting to hear them may have made their voices stand out even more , like hearing an Erhu section in a symphony orchestra . So it ' s hard for me to grasp them not being able to recognize each other . Edit AC