When a baby is learning a language some words must be easier to grasp. You show them a banana and say "This is a banana." You show them a train and say "This is a train." But how can we really be sure that the baby grasps the right meaning for a word that does not refer to some very specific object or action, like "coherence"?
The only way we can talk about the meaning of these words is by using other words; but it seems to me that this necessitates the semantics of these words to be "normalized" in the mind of the baby: when you give a definition for an abstract word, it is going to consist of words which the baby has to understand individually before they can understand the definition. But this is an issue because I do not think anyone has proved that we can define all the abstract words in a non-circular fashion starting from the concrete words.
What the baby could observe if they do not understand all the words is the interrelationships between these different words and then it could find concepts which seem to have the same interrelationship.
But then how do we know the baby is going to have the same semantic understanding as us? For instance, if we were to define "lazy" as the opposite of hard-working and the baby knew neither of those words then it might think that "lazy" means shy and "hard-working" means gregarious. This is not the best example because it is very likely that when the baby will have conversations with other people using these words they eventualy will not parse; but my point is there might be a different way to interpret the words such that the conversations will parse to all the parties involved yet they will actually mean different things to all of them.