Not everything is semiotic. The making of "meaning" is actually what Wertsch argues that it is; all human meaning-making is in fact "mediated action."
However, it is a mistake to argue that language is the only mediated action that makes meaning. It is even a mistake to argue that other semantic/semiotic processes are the only mediated action that make meaning. (E.g. visual, spatial, audio, etc.)
In fact, physical and emotional interaction with people, entities, and things are also mediated action and hence, meaning-making activities. It is a mistake to think that meaning-making is always a conscious process.That is, there are meaning-making processes that cannot be interpreted via other channels.
The making of meaning is the making of a life, a home, a family; it is the intangibility of the space between people.