Slight correction: Zamenhof's native languages (so far as we can tell), in a sense of what he spoke at home, were Yiddish and Russian, although he certainly learned Polish at a very young age due to place of residence. Not that it makes much difference in this case - the quirks of Esperanto phonology, such all those affricates and consonant clusters are familiar to speakers of pretty much any Slavic language. Esperanto orthography, on the other hand, appears to be inspired more by Czech than Polish - "v" rather than "w", diacritics over digraphs etc.