How functionless is junk and how useful is exaptation?

We address the issue of the notion of linguistic functionality in relation to exaptation. Our case is the evolution of the -i/esc- morpheme from Latin to Romance. The exaptive nature of the -i/esc- morpheme used to be considered the historical linguists’ chestnut: from Latin inchoative marker, the -i/esc- morpheme was said to have evolved into a stress-aligning device. The validity of this proposal is questioned in the light of Lass’s definitions of exaptation (Lass 1990 and 1997). Drawing on the historical evolution of the -i/esc- morpheme, we identify several issues with the core concepts of exaptation: (i) junk, (ii) innovation and (iii) functionality. We then argue that exaptation, in its strictest definition (Lass 1990), cannot be said to apply to -i/esc-.