They wouldn't be so popular if they didn't 'say it all' in a nutshell. And everyone knows what they mean. These are two Wingdings symbols. You probably have the font on your computer. You don't see many handsets around like that these days.
Symbols cross language barriers.
They're usefully universal, though they can be local. Down an African gold mine, I noticed the sign for danger was a snake. In Europe it's often an exclamation mark. Here's a banner I designed some while ago. It was for modern wells, which don't look much like a wishing well.