> I have Age - 6 years of experience reading, I have far less than that with whatever icon you come up with.
When I mean icons are a language, I literally mean that they're a language, in that there's a lineage and history of these languages.
For example, I bet you have decades of experience recognizing the 3.5" diskette 'save' icon, and a similar familiarity with the landline phone receiver as symbolizing 'phone'. These are icons that are part of a shared language, so it's safe to say that using them will be instantly recognizable, despite the fact most people don't use floppy disks or landlines anymore.
If a company decides to use a new icon that's not easily recognized, it's like trying to introduce new language; it has to be done smoothly, otherwise most users will not understand what it means. This is not a problem unique to icons; it's a problem across languages.
If I had a new command-line tool that, instead of `./cmtool --verbose`, I implemented `./cmtool --consult` or `./cmtool --magicify`, you'd have to `man cmtool` in order to understand what the commands mean. This is because '--verbose' is a flag that's common oft-used enough to be understood, generally, what it means, while 'magicify' or 'consult' are ambiguous and rarely used. This confusion has nothing to do with the nature that the UI is text-based (vs. icon-based), and everything to do with the fact that user interfaces, like a language, involves shared conventions.