Can you solve this riddle?

What is the one thing in the world that can speak all the languages?

A hint was requested.
A hint was requested.

Here's your hint.
Here's your hint.

Easy Riddle

What goes up and down, but doesn't move?

A Riddle

What do you use from your head to your toes,
and the more it works the thinner it grows?

Riddle De Do...

I am a protector.
I sit on a bridge.
One person can see right through me, while others wonder what I hide.

What am I?