Slip of the tongue
We find that, in order to explain a slip of the tongue, for instance, we are obliged to assume that an intention to say some particular thing had formed itself in the mind of the person who made the slip. We can infer it with certainty from the occurrence of the speech-disturbance, but it was not able to obtain expression; it was, that is to say, unconscious.
The speech disturbance which manifests itself as a speechblunder may, in the first place, be caused by the influence of another component of the same speech; that is, through a foresound or an echo, or through another meaning within the sentence or context which differs from that which the speaker wishes to utter. In the second place, however, the disturbance could be brought about through influences outside this word, sentence or context, from elements which we did not intend to express, and of whose incitement we became conscious only through the disturbance. In both modes of origin of the mistake in speech, the common element lies in the simultaneity of the stimulus, while the differentiating elements lie in the arrangement within or without the same sentence or context.