Answer:
I begin with the letter āiā, if you add āaā in front of me, I become a new word with a different meaning, but still sounds exactly the same. What word am I?
I pass before the sun, yet make no shadow. I'm all around you, but you cannot see me. What am I?
You turn me over after you have travelled far.
When it comes to me, you go on red and stop on green. What am I?
I am enjoyed with a pot and some pointy sticks.
No matter how little or how much you use me, you change me every month.