A crucial point in Well’s argumentation against static approaches to alternation comes from Latin. Interestingly, his point seems to argue at the same time against rule ordering, although neither Wells nor Goldsmith mention this point.
In Latin, pat-tus becomes passus and met-tus becomes messus. This is very difficult to understand in a ‘static’ way (Wells even calls this ‘fatal’, as Goldsmith points out), for instance by only using output constraints. We cannot invoke a constraint *ts and/or a constraint *st, because words such as etsi and este stay unaffected. Only /t/’s which are adjacent to underlying /t/’s turn into [s]. As far as I can see, the only OT mechanism ever proposed which could do this kind of analysis are two-level constraints (which I don’t think anybody is seriously working with).
On the other hand, we can deal with this phenomenon in a ‘dynamic’ way, by positing rules of the following type:
- t->s / _ + t
- t->s / t + _
But we can only do this if we do not order these rules, but let them apply simultaneously. As soon as we order the rules they do not work, or the etsi/este problem arises again. That is the reason why the two-level constraint approach to this is the only one which works as far as I can see: Sympathy, Stratal OT, Comparative Markedness, OT-CC, etc. are all too ‘derivational’.
There also is no clear representational solution (changing a geminate /t/ to a geminate [s], leaving singletons unaffected), since it seems to be a crucial condition that there is a morpheme boundary between the /t/’s.
These thus are very important data, if they are real. Does anybody know about this? Has anybody ever tried to analyze this alternation?