Flash fact (Ep ~ 1)

Growing up, Shu was extremely fluent in sign language, especially due to autism at the time which prevented her from speaking at the time, often using sign language and Morse code to speak. She grew out of it as she grew up and went to speach therapy. But regularly still does sign language if overstimulated, burnt out, or quirk related reasons. (If she uses her quirk too much in one go for long periods of time, her vocal cords temporarily shut off and Shu is unable to speak for a good hour or so.) Her cousins are fluent in reading sign language and can translate in case others can't.

Shu is also fluent in Morse code as stated previously. Being able to have full conversations just by tapping her finger on her chest. Which is actually how she secretly commands her androids in serious situations, as not many people understand Morse code or have the time to decode it. This is how she secretly insults and has her temper tantrums, by angrily tapping her foot to Morse code about her rantings.