En réponse à Michael Poxon <[log in to unmask]>:

> I read somewhere in a linguistics book a few years back how the French
> a-t-il? construction was observed to be reinterpreted as phonetically
> /ti:/
> and syntactically [question particle], which kind of ties in with the
> "should've - should of" debate fiercely raging ;-) elsewhere!

I wonder what dialect of French you're talking about. In French, there is
indeed a construction which is more and more analysed as a question particle:
it's 'est-ce que' (pronounced /Esk/ or /Esk@/) which appears at the beginning
of questions or after the interrogative word which always appears at the
beginning of sentences:

Est-ce qu'il va venir ? /Eskilvav'nir/: is he going to come?
Où est-ce qu'il est ? /u.Eski'lE/: where is he?