En réponse à J Matthew Pearson <[log in to unmask]>:

> Incidentally, how do you know that Arabic treats the copula as
> transitive?
> Couldn't it be that accusative is the unmarked case in Arabic?  (Cf.
> English
> "It is me" or French "C'est moi".)

Well, your remark is interesting, as Arabic has a rather strange way to treat

As for 'to be' sentences, Arabic has various ways to render them depending on
tense and negation. Simple affirmative present equative sentences are rendered
with a 'subject' (called mubtada') in nominative case, and an 'object' (called
a khabar) in nominative case too. One of them must always be definite and will
be the first one in the sentence. Those sentences are nominal. For other kinds
of equative sentences, you have to use a verb, whether 'kaana' for past
sentences, 'yakuuni' for future sentences or 'laysa' (which is not really a
verb but works as such) for negative present sentences. In this case,
the 'subject' is called ism and takes the nominative case, while the 'object'
is still called a khabar, but takes the accusative case. Finally, with equative
affirmative present sentences beginning with 'inna, or its "sisters", the
subject (called ism) takes the accusative case, while the 'object' (still a
khabar) takes the nominative case.

So the situation is quite complex, but if you look at the nominal sentence, it
seems that nominative is the unmarked case.

Now comes the strangest thing: adverbial expressions like "chukran": thank you,
are in fact nouns in accusative indefinite case. Can they be considered marked,
or does it mean that accusative is the unmarked case?

As you see, Arabic cases have quite a complex behaviour. Another thing I'm
thinking of taking for my Arabo-Romance lang (I already did it a little with
Reman which always follows its conjunctions with an indirect personal pronoun
subject of the verb of the subclause, if the subject is not expressed by a