PyTorch Said SIGILL. My Raspberry Pi Said No. Local TTS on ARM Explained.

I spent a Friday morning installing a local text-to-speech engine on a Raspberry Pi. It compiled fine, dependencies installed cleanly, the model loaded - and then it crashed with a signal I hadn't seen in a while: SIGILL. Illegal instruction. Here's what happened, why it happens, and what to do instead. What I Was Trying to Do My AI agent currently uses cloud TTS - ElevenLabs for English, Sarvam. AI for Indian languages. Both are good. Both require an API call. I wanted to explore running TTS locally on the Pi so the agent could speak without phoning home.