father: baba 爸爸
Mother: mama 妈妈 (nearly the same with english :)
brother: gege 哥哥(older brother) ;didi 弟弟 (younger brother)
sister: jiejie 姐姐 (older sister) ; meimei 妹妹 (younger sister)
grand mother: Waipo 外婆 (mother of your mom) nainai 奶奶 (Mother of your dad)
grand father: Waigong 外公 (father of your mom) yeye 爷爷(father of your dad)

okay..if you have any pronunciation problem, just contact me :)