How to prep for a first call with a native speaker without sounding like a textbook?

I'm finally meeting a native Xhosa speaker for a casual chat next week and I'm terrified. I want to sound natural, but I’m worried I’ll rely too heavily on formal textbook phrases that might sound stiff or outdated. I’ve been using Chickytutor.com to roleplay common interactions and get corrections on my flow, but I’m wondering if there are specific 'street' conversational fillers or idioms I should know to make my Xhosa sound less rigid?