The change of language is going to be revealed once the project goes public though. What then? What are you supposed to answer when people start asking why you didn't use the language you said you'd use?

This is so incredibly psychotic, you'd have to walk on eggshells and make sure to never publicly talk about your choice of technology stack to not upset you people. No, people are allowed to talk publicly about what language they pick for their projects, and they're allowed to publicly disclose when they reconsider. Anything else is literally insane.