I'm not sure it's that fringe. Popular addages such as 'language is a vehicle for thought' and 'the pen is mightier than the sword' reveal that language is sometimes implied to be tool-like, with many of our unspoken acts carrying linguistic meaning (e.g. ghosting, not answering a call, sign language, gesturing, nodding, etc.).
Even tools present us a certain 'language', talking to us via beeps, blinks and buzzes, and are having increasingly interesting discussions amongst themselves (e.g. subreddit simulator, agent based modeling). Recent philosophers of technology as Mark Coeckelbergh present a comprehensive argument for why we need to move away from the tool/language barrier [0], and has been part in informing the EC Expert Group on AI [1].
I think what you’re saying supports the view that language is structured and actively used—which excludes pheromones. But I don’t see how you get to the next step, of characterizing unspoken acts as carrying linguistic meaning. That is, sign language and not answering a call aren’t obviously in the same category, precisely because not answering a call fails to communicate any particular concept, and because people don’t use various modes of non-answering to communicate various things.
Even tools present us a certain 'language', talking to us via beeps, blinks and buzzes, and are having increasingly interesting discussions amongst themselves (e.g. subreddit simulator, agent based modeling). Recent philosophers of technology as Mark Coeckelbergh present a comprehensive argument for why we need to move away from the tool/language barrier [0], and has been part in informing the EC Expert Group on AI [1].
[0]: https://www.taylorfrancis.com/books/mono/10.4324/97813155285...
[1]: https://philtech.univie.ac.at/news/news-about-publicatons-et...