Why Polish-American polka? Because among polkas, we think it looks the snazziest. But you be the judge.
Polish-American polka -- which Morley Leyton tells us is not danced in Poland -- is distinguished by "the bounce", which is really stepping on bent knees and then rising before stepping on a bent knee again.
And then there is the hop. There is an option to hop or not. The option to hop appears in most polkas, usually on the 4th count of a measure ( "step step step hop" ). In Polish-American polka, the hop is after the 4th count and before the 1st count ( "step step step and a-step step step and a-" ).
The pages which follow presume that the student has some other dance experience and knowledge of dance terminology. Best of luck.