En réponse à Andreas Johansson :

>It was argued that a verb like "to sell" logically should have four core
>arguments - the seller, the buyer, the thing sold and the payment - but that,
>for some reason, no known language has verbs that take more than three core
>arguments, so one of those arguments can only be introduced as an oblique (in
>the case of English "to sell", the payment; "he sold me the book for ten
>euros"). The conclusion drawn, IIRC, was that this limitation is hardwired
>into the language-handling parts of the central nervous system.

Maybe it has something to do with another hardwired limitation, which seems 
to be that the human mind cannot handle more than around 7 entities 
simultaneously (i.e. our immediate memory is limited in size to around that 

Christophe Grandsire.

You need a straight mind to invent a twisted conlang.