Query: Negation and case marking

[john.stewart at IUED.UNI-HEIDELBERG.DE]

Dear Matti,

There is a related, but maybe not directly relevant phenomenon in Arabic.
Modern Standard Arabic has various negative particles that
occur together with verbs in different tenses and aspects. But
"equational" sentences in the present tense work differently (Arabic has
no copula). In a positive equational sentence, the predicate is marked
with nominative case.

'as-samaa'(u) saafiya(tun)
DEF.ART-sky-NOM clear-NOM.INDEF
The sky is clear.

But in the negated counterpart to this sentence, the negative verb
'laysa' is used, and the predicate then takes the accusative case:

('a)s-samaa'(u) laysat saafiya(tan)
DEF.ART-sky-NOM is-not clear-ACC.INDEF
The sky is not clear.

On the other hand, it is not only the negative verb 'laysa' that can have this
effect on phrases in the predicate; adverbs in Arabic are always in  
the accusative case.

Corrections/elaborations are welcome from anyone better versed in  
Arabic grammar!

Cheers,
John Stewart