Wittgenstein’s not talking about interpersonal games in the sense that you seem to mean. Wittgenstein uses the term language-game to describe a rule-following activity, which is what we do when we use language (language by definition is a rule-governed activity). He starts off the Philosophical Investigations by giving us an example of a primitive language-game. In Wittgenstein’s example there is a builder and his assistant, when the builder calls out the word slab , the assistant either brings the right stone or he doesn’t. By bringing the right stone the assistant shows that he understands the rules of the game, if not, then the assistant hasn’t learned the proper response to the call. In other words, the assistant by bringing the wrong stone hasn’t demonstrated a mastery of this particular language-game. A further example can be seen when thinking about how a child might learn to use the word cup, depending on how the child responds, this demonstrates their mastery of the language-game, namely, how they respond to the word/s.
A rule-following activity is not learned in isolation (see private language in the PI). We necessarily learn rule-following in conjunction with others. The logic of rule-following is necessarily connected with making mistakes; and correction only happens with others who know the game. Think of how you learned simple mathematics. If you learned it in complete isolation you would never know if you were making errors, because whatever would seem right to you, would be right.
Now, if we bring this back to the subject at hand, knowing and doubting are learned in the same manner, one cannot simply choose to use these words any way one likes. These words (knowing and doubting) are not learned in isolation, but are governed by the rules associated with their particular language-game.
He is saying that you cannot have private language games. I am saying that being with yourself is not private, which can be seen and then internally noticed that we treat ourselves as other people all the time. We are never alone.
Parts of me do this in relation to each other all the time. Of course the ‘objects’ are often more abstract. Like ‘stand up for yourself’ ‘be more expressive’. And the dynamic is between parts of the self/brain/soul (depending on one’s paradigm). One can track this introspectively, MRI wise, or in watching others, how they succeed or fail.
Yes, we model the intrapersonal activities and interpersonal ones, but we learn those real early. You can see even very young kids talking to themselves and reacting to their own speech. We are complicated.
And actually I have to think about this, because I don’t think our brain regions necessarily get along or have the same approaches. It may be that neurosis/self-division is built in and not even cultural/empirically based. We may be a few people/personalities from the get go.
Which includes ourselves.
We may learn the words in isolation, but we will tweak them our own idiosyncratic ways and apply them uniquely, though this is not exactly related to what went above.