He`s just a crossdresser, and has a strange accent.
His accent is his valley-girl dialect (like adding -nyo to the end of sentences, I'm not too sure though...). There is no exact confirmation as to Poland's sexuality. The only characters that have confirmed sexualities are Sweden and France.
Edit: The person above is partially correct, but they are stating "facts" they do not know for sure. The author of Hetalia never confirmed whether any characters are gay, except for Sweden kind of, because they would rather have fans choose for themselves. So we fans can decide which couples we'd like to ship. I personally ship Lithuania X Poland, but if you want Poland to be straight then he is.