Sly was born before his twin Sam, but also didn't start talking as a child until about 6-7 years old. Instead, he'd relay any communication to Sam through gestures (or rare whispers to his brother) rather than talking to anyone. They later learned sign language which he still uses on occasion.

Conversely, Jericho is a few years younger than his sister Kit. Though the baby of the family, he's always been more motivated and driven than his sister, sometimes to the point of naive idealism vs her natural skepticism towards everything.