The part of a contract no one reads or what a tiny kitten makes

I'm the language of secrets one opts to share Spoken not with the voice, but a breath of air Or a similar sound, sibilant sans speech Like breeze through trees or hissing waves at the beach

I visit your wallet when luck has run dry, I split sturdy friendships and promises awry. I shout from old radios when headlines erupt, I hide in the silence when patterns disrupt. You fear me in rules, crave me in news, Repairing or sharing, it’s me that you use.

I fly away when you throw me, Then I turn around and come back to you. I’m not a bird, but I always return. What am I?

We’re not related. You can get that in writing.