One should also notice that Basque in some
> >few verbs still has _inflected_ progressive tenses;
>
> That's because the periphrastic form is no longer truly a
> progressive:
>
> I go = joaten naiz
> I went = joan nintzen
> I'm going = noa
> I was going = nindoan
>
> The specialization of the synthetic forms as progressives
> (in the few verbs that still have them) is surprising. One
> would have expected the opposite to have happened.
>
In other words a situation where those synthetic forms _originally_
were progressives would be less surprising, and, if Vennemann is
right about his West European Vasconic substrate, it might be
imagined to have been the original motherlode of progressive tenses.
Note btw that Italian, Spanish and Portuguese are using not the
present participle for their progressive tenses, bur the Latin
gerund, as if such sentences were copula-less predications with an
inflected infinitive in an unmarked(?) locative. One might also
include French <en [verb]ant> as a locative progressive (albeit a non-
finite form). Danish uses the infinitive in one of the two
progressives: <... er ved at [verb]e>, lit. "...is at to [verb]"
Torsten