[thristian]

You're butting your head against the fundamental paradox of communication: in order to communicate an idea that's in your head to somebody else, you have to encode it in a way that the other person will recognise and decode; that is, you need to already have some shared context. However, if you have a new idea then by definition it can't be part of the shared context, so it can't be communicated.

We get around this by invoking combinations of existing ideas and hoping that the recipient puts them together in more or less the right way: we might say "a leopard sits in the tree to your left", invoking the existing ideas "leopard", "tree", "to your left" and "sits", which can be combined in the obvious way. UML, musical notation, mathematics... all these are variations on "language" in the sense that they have a vocabulary of existing ideas, and a grammar of natural ways to combine them, and so you can bootstrap ideas in another person's brain by giving them pieces they already know and hoping they can assemble the idea correctly.

Language is messy and non-portable and unreliable, and it is exactly those properties which allow it to convey novel ideas from one person to another.

[mjburgess]

We get "around" this by ostentation: words in a spoken (natural) language refer to the world.

I point to examples of trees and say "tree", etc.

"New" ideas are acquired by example -- language is not a closed system.

[Ma8ee]

Which is harder than it sounds if you are trying to do it from scratch. Even pointing is a part of language, and trying to convey that concept is far from trivial. I think a big part of language learning in children involve the child seeing other people react to language and imitates. E.g., father points and mother gaze in the direction of finger, child follows mother's gaze.

[musingsole]

To further this idea, dogs intuit the meanings of commands, some more easily than others, but teaching a dog to understand a human pointing at something is hard. My own dogs seem to interpret it as "just keep looking"

[amelius]

We need a universal translator,

https://en.wikipedia.org/wiki/Universal_translator