> There's a view that suggests that language is intelligence.
I think you find the limits when you dig in. What are you calling language? Can you really say that Eliza doesn't meet your criteria? What about a more advanced version? I mean we've been passing the Turing Test for decades now.
> That language is a requirement for understanding.
But this contradicts your earlier statement. If language is a requirement then it must precede intelligence, right?
I think you must then revisit your definition of language and ensure that it matches to all the creatures that you consider intelligent. At least by doing this you'll make some falsifiable claims and can make progress. I think an ant is intelligent, but I also think ants do things far more sophisticated than the average person thinks. It's an easy trap, not knowing what you don't know. But if we do the above we get some path to aid in discovery, right?
> that you might not be able to hold an idea in your head until it has been named
Are you familiar with Anendophasia?
It is the condition where a person does not have an internal monologue. They think without words. The definition of language is still flexible enough that you can probably still call that language, just like in your example, but it shows a lack of precision in the definition, even if it is accurate.
> Perhaps it is why other animals on this planet seem to us lacking intelligence
One thing to also consider is if language is necessary for societies or intelligence. Can we decouple the two? I'm not aware of any great examples, although octopi and many other cephalopods are fairly asocial creatures. Yet they are considered highly intelligent due to their adaptive and creative nature.
Perhaps language is a necessary condition for advanced intelligence, but not intelligence alone. Perhaps it is communication and societies, differentiating from an internalized language. Certainly the social group can play an influence here, as coalitions can do more than the sum of the individuals (by definition). But the big question is if these things are necessary. Getting the correct causal graph, removing the confounding variables, is no easy task. But I think we should still try and explore differing ideas. While I don't think you're right, I'll encourage you to pursue your path if you encourage me to pursue mine. We can compete, but it should be friendly, as our competition forces us to help see flaws in our models. Maybe the social element isn't a necessary condition, but I have no doubt that it is a beneficial tool. I'm more frustrated by those wanting to call the problem solved. It obviously isn't, as it's been so difficult to get generalization and consensus among experts (across fields).