UPDATE :
1) this post is supposed to be an answer to the main thread.
(Sorry herveus, I goofed when answering...)
2) Thanx dragonchild for pointing out an error (when I switch from hash to array, I should also remove 'keys' ;-)
IMHO you can/should learn from every language.
(Even with COBOL I learnt a lot about file IO, Indexed files, EBCDIC prob...)

I believe that each new language may give you another way to see (and thus solve) problems...
Pascal taught procedural programming, and OO basic programming (it was an object pascal).
C taught me to use memory and loops eficiently and gave me a first contact with "Unix semantic".
<UPDATE>>
Smalltalk influenced the coding of a lot of experienced coders here...
Ruby influenced the coding of another experienced coder here...
</UPDATE>>
Prolog taught me to think in term of predicate, recursivity and backtracking.
Lisp taught list processing, but I didn't understand/like them util I've found Perl...
(Btw in my mind Lisp will always be more about lambda calculus than about list)

I really discovered list with Perl (Lovely map and grep...).
I hardly imagine using other structure as efficient and evolutive as hashes...
the for my $var (@mytab) definitly took over my old C for(my $i=0;$i<=$#mydata;$i++)
It's not only a matter of syntax, it's a way to 'see' your structure, to 'think' your interface
(to be always evolutive, using hashes..) and your looping differently...

So, to be short a new language will often bring you new solutions/point of view
(in the 'old time' people were saying 'paradigm' ;-)
which can only enhance your ability to solve problem cleanly and efficiently (ie: enhance your programming skill)

"Only Bad Coders Code Badly In Perl" (OBC2BIP)