Incognizable

Because Tom just woke up, his speech is incognizable.

1658, Thomas Saintserf (translator), Entertainments of the Cours: or, Academical Conversations, compiled by Melchior de Marmet, London, p. 104, A dead Body is always incognizable, not only because it is ordinarily changed, but because it neither speaks, nor acts; and for that the qualities of its Soul, which we should know, are departed with her, and have left nothing but a trunk, and a lump without motion.

The lettish race […] was not a primitive stock, as the finnish, the germanic, or slavonian, but a distinct branch, now become incognizable, of the Slavi […]

[…] if therefore position is, to the nascent intelligence, incognizable except as the position of something that produces an impression on the organism; how is it possible for the idea of position ever to be dissociated from that of body?

All this time the incognizable nouveau was smoking slowly and calmly, and looking at nothing at all with his black buttonlike eyes.