Your explanation is absolutely superb. I modified my drl as per your suggestions and it's just been completely transformed. Just one question regarding one suggestion below :

-- is this something like a for each loop in java . This is the first example i have seen in drl

In a way, yes. Since
Foo( ... ) # match any Foo according to constraints, if any
Bar( ... ) # match any Bar according to constraints, if any
these two patterns produce the Cartesian product, such as a nested loop does. BUT, the order of the pairings is indeterministic, and changes in WM might influence this loop, even make it infinitive. Therefore, "in a way".

-- will this automatically iterate over as many languages as have been inserted ?

That's the whole idea :-)

-- the inserts .. don't they have to be within a rule block ? or did you just omit other things to keep it simple

You can do it in the Java application framework. You can also write a high-salience one-shot rule such as

rule "1st shot"
when
then

insert( new Language( "Japanese" ) );
insert( new Language( "French" ) );
// more of the same

end

Cheers
Wolfgang