The Polish languge does not contain articles such as, a, an, the, thee, thou.
Actually, thee and thou are not articles. They are personal pronouns, mostly archaic, and they do have Polish equivalents.
There are 35 letters in the Polish Language
You probably meant the alphabet, since languages do not have letters, but sounds, and often there are more sounds in a given language than there are letters in its alphabet.
Official Polish alphabet has 32 letters (Q, V i X are used only in foreign words or borrowings)