Offline, Embeddable Speech Recognition?

I am in shop for a speech recon library that works offline and can fit on a phone (Android).

I used to use Snips AI (https://snips.ai/), which worked well until it was acquired by Sonos. Now the portal is down and I can't modify the model anymore.

Looking for something ideally written in C or that can target C for portability. Free/libre and copyleft preferable to avoid the acquisition trap again.

Tapping into the vast pools of knowledge of HN; could you please suggest alternatives, preferably ones you have experience with?

Thank you.