Here's a recent conversation that I had with my 7 year old daughter, Skyler...
Me: As of right now, we don't have any plans for the weekend. So, we can go to the movies on tomorrow.
Skyler : You shouldn't say that, Daddy
Me: Say what, Skyler?
Skyler: You shouldn't say "on tomorrow".
Me: Why not? We're going to the movies on tomorrow. Do you not want to go?
Skyler: That's not what I mean, Daddy. Yes, I want to go tomorrow. But you said it wrong.
Me: Huh? I'm confused
Skyler: You said we were going "on tomorrow". You shouldn't say "on tomorrow". You should just say "tomorrow." You should have said "We can go to the movies tomorrow."
I paused for a second. I had to really think about what she was saying. I was surprised that she said it but i was also wondering why a person like me, who loves the English language and speaks it well, was being called to the carpet by a 7 year old. My first thought was "Is she right?" Then, I thought "Where did she learn this?"
I gathered myself after a few seconds and I replied...
Me: You're right, Skyler. There's no need to say "on tomorrow"...it's just "tomorrow". The word "on" is negated or cancelled by the tense of the word "tomorrow". So, you're right
Skyler: Actually, it just sounds better, Daddy.
Wow...i just got schooled by a 7 year old!