Atomic Fact and Language-Game

In the Tractatus, Wittgenstein asserts that there exist Atomic Facts in the World, without specifying which states-of-affairs they are, e. g. Cogitos, Sense-Data, etc.  Now, one candidate is the oral speech-act, for, as has been previously discussed, such an Utterance is inseparable from the process that produces it.  Furthermore, it is similarly arguable that any instance of one is inseparable from its circumstances, which includes, at minimum, an utterer, an addressee, and some purpose which it serves.  In other words, an Investigations' Language-Game can be conceived as a Tractatus' Atomic Fact.  Thus, one transition from the Tractatus to the Investigations need not involve some mystical epiphany--it is merely a road not taken within the earlier work from one of its premises.