One of the reasons for why we adamantly and anxiously protect our right to speak is because it is a means of validation. It validates our identity as independently thinking beings, it acknowledges that we are capable of expressing our thoughts/beliefs/opinions, and it allows us to 'own' the notions that drift in and out of our heads. Rather than launch into some politicized verbal-vomit on the right to free speech, I'll take you into a life memory:

She gave me a quick .005 second glance, looked up at the clearly taller adult male figure standing next to me and proceeded:"What grade is your daughter in?" The woman asked my dad.
Sitting in my wheelchair next to him I watched the verbal table tennis match carry-on over my head. The serves and spins each side took were happening too quickly for me to jump in and interfere. The woman began shifting her eyes from me, and then back up to him. I could feel my dad gripping and twisting the foam handles on my wheelchair. His frustration under wraps, he hid it well. I held my breath uncertain of how the match would unfold, but silently pleading for a Team Dad win! In a matter of seconds it took only a slight tap of the ball for my dad to send his final, and victorious serve to the other side and catch her off guard: "You can talk to her, she's 19. She's an adult now." My dad responded, with a good-natured smile.
"Oh! Okay!" The woman quickly replied - simultaneously her eyebrows raised, and her neck jerked back in disbelief. She then knelt down next to me with audible crackles in her knees, the sounds of defeat and a polite gesture to the victor.

This is not some bizarre phenomenon that rarely happens. It's a fairly frequent occurrence, and happens regardless of who I'm with! Surely we can agree, no matter where we stand on our rights or freedom to speak, that the above incident is totally weird - right?
My dad was right. I was 19 at the time, and I had become an adult. But being a legally-recognized adult wasn't the reason for why the woman should have directly asked me her question. She should have asked me because I was capable of speaking for myself. I was more than capable of answering her question. And because the question was about me, not about what grade level my dad was in.

For awhile my parents, like many parents of young kids, spoke for me. They told people who I was, what I liked to do, what I could or could not do, what I needed etc. But it got to be a certain point where I began to figure some of those things out for myself - and it validated my progress as a maturing individual to be able to express my own ideas on those things!
After that point whenever someone answered for me, (be it friend, sibling, doctor, classroom aide, parent, relative..) it took away the life experiences and conclusions I came to for myself. Over my head they answered for me, and down below this is what I heard: whatever you decided doesn't matter. It also told me: you should expect others to speak for you, you can just sit back and let them do the work. It said to me: whatever people say for you is the right thing for you. In a literal way it blurted out: you can't have these conversations because they are literally above your head, out of your reach. Whether people intend to imply these things or not, through their manner of communication, isn't what's important here. It's the fact that internalizing those implications were tough for me to first accept, then reject, and eventually find solutions for this bizarre behavior.

"Well actually, I just finished 13th grade." I responded to her wide-eyed puppy dog face. After hearing my answer she looked puzzled. I decided to cut out my smart-aleck answer and said:
"I mean that I just finished my freshman year of college."
"Oh, okay. I get it now." Gone was the look of shock and disbelief from her face. All that was left was a blank-slate, the groundwork for mutual respect and understanding.