How to sound less like a character

Sorry if this isn't the right place but I can't post on the jplearning subreddit.

My girlfriend is learning Japanese and has been for a few years. I'm planning to start like properly learning but for now I've been just picking up a few phrases from things we watch and what she teaches me and then I use them with her throughout the day. All I know is some basic phrases/questions and my timestables.

Which is fine except she always says I sound like a red sentai ranger when I talk. I'm guessing it's my inflection but I'm not sure what about how I talk is causing that and don't know to not do that. Any suggestions?

by CrescendoNoMelody