Letter Xx Xylophone – [zahy-luh-fohn] – /ˈzaɪ ləˌfoʊn/ X-ray – [eks-rey] – /ˈɛksˌreɪ/ Ox – [oks] – /ɒks/ Six – [siks] – /sɪks/ Related Posted in English Workbook Level One, Letter Xx.