How does the dialect and setting add to the short story "The Last Leaf" by O. Henry?

The setting of old Greewich Village with its leafy streets and ivy-covered two-story brownstones is an appropriate one for two young aspiring artists who need a place that has low rent, as well as a location where they can join other artists in the area. Old Behrman, who lives on the first floor, has a Yiddish accent that lends color and authenticity to the story. He is probably from Germany, one of many displaced Jewish persons from Europe who have come to New York.

Behrman may have had to flee Europe; at any rate, now he has little. But, he holds to hope, "the thing with feathers/That perches in the soul" as described by Emily Dickinson. For, Behrman hopes that one day he will paint his masterpiece. And, of course, he does because it is his painting that saves Johnsy from death.

When Sue, Johnsy's roommate, summons Behrman to pose for her, she reveals that Johnsy has pneumonia and now feels that she will die when the last leaf of ivy falls from the brownstone. Hearing this, the old curmudgeon is angered,

"Vass!" [What] he cried. Is dere people in de world mit der foolishness to die because leafs dey drop off from a confounded vine? I haf not heard of such a thing. No, I will not bose as a model for your fool hermit-dunderhead. Vy do you allow dot silly pusiness to come in der brain of her? Ach, dot poor leetle Miss Yohnsy."

Yet, there is something endearing about his candid tirade. Certainly, his wrath is nothing to be feared because when Sue says, "Mr. Behrman if you do not care to pose for me, you needn't," he contradicts her, "Who said I will not bose? Go on. I come mit you." And, it is fortunate for Johnsy that he does because he is moved by his love for the young woman so much that he goes out into the winter storm and paints an ivy leaf onto the window. By his doing so, the "last leaf" will not fall and put Johnsy into despair.

Indeed, the Greenwich Village setting of young artists and the Yiddish accent of the colorful old Behrman lend a certain poignancy to O. Henry's story as well as some added color to the tragic circumstances of Johnsy's illness and Behrman's sacrificial death.