Did you find your ancestor on 1930 census? That is the census that would say Na-naturalized, Al-alien or Pa-first paper.Did he die in America?If yes, his death certificate should be obtained and might contain the information you are looking for. If he was not naturalized and lived pass 1940 than he had to fill out an Alien Registration Form. It is all in pronounciation.The English CH is CS - Hungarian, C^ -Slavic (Slovak, Czech, Croatian, Slovenian). Was he Roman Catholic or Serbian Orthodox? In Croatia's phone book: PAPOVIÆ, POPOVIÈ Keep in mind that birthdates were not celebrated or needed like they are in today's life so a year up and down no biggy. Mistakes were made then and now.