In other conversations my grandson and I shared the idea that many things have value simply because people agree that they do.
For example, why is gold considered so valuable? Yes it's shiny, pretty, and can be made into objects but so can plastic. Gold is rare, but so are many other elements. Gold is valuable simply because people agree that it is, but someone stranded in the wilderness and struggling to survive would find food, water, and shelter much more valuable.
The same thing applies to language. Words only have meanings because people who need to communicate with each other agree on them. Sometimes one word my be considered offensive while a literal synonym is perfectly acceptable and, again, that's only because people in the culture agree about that.
Humans have many differences, but at least there are a few things we do agree about.