According to the OED’s examples, Lewis Carroll may have invented the use of ‘portmanteau’ to mean a word made up of the elements of two or more other words in order to somehow combine their meanings: in Through the Looking-glass, the words slithy and mimsy, which he coined for the poem Jabberwocky, are called by him portmanteau words (slithy = lithe and slimy; mimsy = flimsy and miserable).
Nick Robinson created another for the Today programme on BBC Radio 4 on 28 November: /ËˆrÃ¦pÉªdÊ’ÉªÅ‹/ (I hesitate to put it into traditional orthography). It was a purely accidental coinage, and one which he immediately noticed (slips of the tongue often pass unnoticed by the perpetrator, and are sometimes even denied when pointed out to them), and corrected, in both ways. He meant to say either “wrapping” or “packaging”, but for some reason his brain mangled the message on its way to his mouth, and a mixture of the two words was the result.
I suppose you could say that in Saussurian terms, the “langue” was correct, but the “parole” slipped, or to use Chomsky’s words, the competence was there while the performance left something to be desired.