I think when we talk about change of the meaning of the words, we need to differentiate two things. One is change that comes from knowledge about the correct use of the word, and the other is change of meaning that might come from the knowledge about whatever it is to which the word refers.
If two people don’t mean the same thing by the word because of misunderstanding of what the word is supposed to mean.
- If one of the parties in semantical disagreement is taken to be expert on what the word is supposed to mean, the disagreement is resolved by the expert correcting the wrong usage of the word of the other party. Such is the case I think with the children and their usage of words described in the previous post. The children being aware just that the things can show gestalt perceptual similarity, don’t have anything else to connect the word to. So to say, because they aren’t (at that time) aware of any other kinds of similarity between the things, they do their best with what they are aware of. But in this case adults are taken to be expert of the usage of the words, and through the years by explaining, pointing, describing children become aware of other kinds of similarities, and connected to that can correct their use of words. We can say that what is changing here is both the knowledge about the world, which opens possibility for learning the correct use of the word.
- If none of the two parties considers the other one (or others) as an expert, either they will be pragmatic or they will end up fighting.
As Richard pointed in the comments of last post, if people can mean different things by the same word is not an issue. I acknowledge that point, and I think that nobody has (or should have) problem with change of meaning of words which is motivated by learning or by pragmatic decision about use of words, and which (I think) would cover the cases that appear in cognitive development.
So to make the issue which I raised in previous posts more specific – it is not just if there is possibility of change of meaning of the words, but if a change of the meaning of the word can happen among the competent users of the word, which are in same time also experts about what the word refers to.