Let's rewatch the trailer for Fishtank real quick
https://youtu.be/j6T0VG-F4vIJosie appears at 00:38 and 01:00
Why doesn't she talk like that anymore? She only didn't talk with her spergie monotone robotic voice during impersonation challenges and she couldn't fake her "normal" voice tone for too long. Was she nervous because their parents were watching 24/7? Was she overly conscious of being filmed nonstop? She still talks like a quirky robot after the tank, what is up with that? She also talks normal on old videos of her with Winston.