It began in pre-kindergarten at age four. Kids would yank my hair hard for fun, because if they pulled hard enough I would bend over in the direction they pulled me, and I would then stay that way, bent over without moving, till someone pulled me upright. They also mobbed me in the coat room and their game was to knock me down and see how many of them could fit sitting on my body at the same time.
Of course I never spoke or made any sounds either, even while being attacked, and the teachers would only find them abusing me by sheer luck. Because I couldn't speak, I could not ask to go to the bathroom either. So each day, I wet my pants; not because I didn't want to go to the toilet, but because I couldn't bring myself to ask permission to do it.
My main goal daily was to escape from kindergarten and run away home, even though I didn't know how to get home from there. But I made quite a few escape attempts. While inside, my main activity was to slowly scrape the paint off the wall with a small scraper, like a sharp pebble. I collected these powdered paint scrapings in a little cup, and that was my only interest in being there. I never played with any of the toys or games, nor with other children. Of course it drove the teachers mad that the paint was being systematically scraped off the walls, but no amount of yelling or punishment had any effect on me whatsoever, and I'd return to doing it as soon as possible.
Seeing how insane I was making the teachers with my escape attempts and my paint-scraping, some of the other children decided that was cool and began escaping and scraping paint too. There actually developed a secret underground paint-scrapings black market, with children competing about how much scrapings they'd collected without being caught. But that's didn't make me any more popular, just slightly less weird in that one way -- I had unknowingly started a fad.
Despite this amount of overwhelming weirdness, nobody seemed concerned for my mental health. I was scolded for "misbehaving" all the time, yet praised for learning to read fluently at such an early age (4). Neither their scolding nor their praise had any effect on me whatsoever. "They" were not even in my world, and so long as they left me alone I was happy to continue collecting small twigs and scraping the paint off the wall, speaking to no one, and peeing my pants.