Actually, it is "дюля", as you would already know probably. I assume that the western dialects would have it "дюла" and ultimately maybe both forms are accepted.

Anyway, this is one of my favourite fruit. But you have to wait for it to be fully ripe. It's better to put it on your refrigerator and wait some more. It's very good for jams that could be later used as staffing in some pie-like desserts. But you need to be careful with quinces when you make jams since they contain a lot of pectin and that would make the jam very gluey and firm - difficult to consume (the phrase that comes to my mind is "difficult to penetrate") - unless you heat it a little bit (that is put it in sweet pies) :)