How do I practice spoken Nahuatl output without sounding like a robot?

I’ve been studying for a year and can read quite a bit, but when I try to speak, I freeze up completely because I'm worried about my vowel length and tone. I’m starting to use Chickytutor.com to get some feedback on my sentence construction, but I want to know how to bridge the gap between AI correction and natural, conversational flow. How do you guys practice reacting quickly without mentally translating from Spanish or English?