The inner speech is not a counterpart of the external one. And we should classify a discourse as internal or external without any reference to its form of expression.
In fact, they are two different kinds of discourses. The discourse spoken to yourself is related to others by confronting them in their supposed strength. They are represented with such a hardness, as if they would not be just one’s stubborn partners of conversation, but also the bearers of a precise mind, which seems to be in a closely simile to that showed by the concepts and propositions. Thus, the inner discourse tend to become a conceptual or proposition intermingling, even if it is meant to go out from itself to the benefit of others.
On the contrary, the external speech borrows the looseness of the multitude of beliefs supported by its listeners, even if it is the case of a precise discourse. The external discourse should be analyzed according to its looseness. It should be questioned how a precise thought can provide the contradiction of being also the indefinite set of words repeated and surely misunderstood in the free act of listening.