Let us posit for the sake of argument the existence of a nonhuman intelligence. Sentient critters from the planet Xunga or some such thing.
One could say that it would always be a matter of interpretation on someone’s part to say that the Xungans and the humans are in agreement about the meaning of Aspect J of the universe, and that perhaps someone else would arrive at the conclusion that actually the Xungans and the humans are not so much in agreement there after all. (But then one could make the same kind of point about whether or not the humans are in agreement with each other or if in fact there is no consensus about Aspect J).
For now, let us say that you and I are convinced, at any rate, that the Xungans and the humans are indeed in agreement about Aspect J of the universe. In your terminology does that make the meaning of Aspect J “human assigned” and also, coincidentally, “xungan assigned”? Does it not elicit the philosophical possibility that Aspect J has characteristics or properties (meanings, if you will) that both the humans and the xungans perceive?
Then there is Aspect K, about which the humans and the xungans definitely seem (to us, to you and me) to have a different take on. We could speak here of the “human assigned” meaning and the different “xungan assigned” meaning. Is it reasonable to posit that there is, in some useful sense, a More Complete Meaning or More Accurate Meaning of Aspect K, such that if the humans and xungans studied each other’s “take” on Aspect K they might attain, incorporating and consolidating and mutually clarifying previous understandings, until the humans and xungals would reach an accord of understanding regarding Aspect K?
To be sure, it would also be my assumption that in order for the humans and xungans to see Aspect J or K the same way, they (the humans and xungans) have to have traits in common. Because (to reiterate ground we’ve agreed on already) meaning is meaning “to an audience”, and for the two species to be part of the same audience implies a commonality of perception.
Another immediate question then: Could it be that the mere fact of being an intelligent life form gives one sufficient commonality with any other intelligent life form to be able to attain perception in common?
As you can see, this can indeed converge towards the position that “there is indeed a correct and true meaning” as well as “people can perceive things to have a certain meaning, and people can also perceive things inaccurately or wrongly and thus attribute to them the wrong meanings”. Although I don’t think it so readily lends its support to anyone attempting to claim “and furthermore we know for sure what they are”.