I don't know their language. How do I communicate the idea of "time travel"?

I figure that being so far in the future, and with these gigantic buildings and delicates clothing, these people are probably highly advanced. So I point at the sun, and make gestures to describe its movement across the sky. Then I indicate it happening again and again, as if days pass very quickly. The little man seems very interested. He makes sounds of thunder and mimes the shape of falling rain. After a while it becomes clear that he thinks I came from the sky, and then grew from the ground like a flower. Then they all get excited and start picking flowers and making necklaces from them, and they all dance and giggle. I am shocked. I assumed the future would be highly advanced and I'd learn great things. Did I build the time machine for nothing?

They really want to take me to see their friends. Should I go with them? Or should I try to learn their language? Or explore the area? Or do something else?