Does this mean that they can be used in any platform regardless on whether they are officially supported by the design language’s creators?
You want to know if they are protected by something like copyrights?
AFAIK, those two are not, but you’ll get a useful answer if you look at their terms of use.
You can’t copyright a color palette or a design idea, but in principle you can violate trademarks or design patents by copying those two. Again, AFAIK, not the examples you posted, but in general those things could be protected.
I often take a look at Material design’s color palette when I need colors. It’s nice to follow them and it’s also nice to take hints from them.
Yep, they’re not languages anyways. Whatever it technically is, whomever decided to call it a language has got their head up their butt
“Design language” is, without a doubt, a thing. It’s a metaphor, and a pretty apt one. Curious to hear what you think of programming languages.
Design guidelines?
Yes. A good example is any Google app on an iPhone. They eschew iOS design language for Material design.
