U.S. diplomat: Language key Yoko Mizui Daily Yomiuri Staff Writer For Joyce Wong, principal officer and consul of the U.S. Consulate in Fukuoka, listening comprehension practice was the most difficult part of her studies at a Japanese-language school run by the U.S. State Department in Yokohama. U.S. diplomats who need Japanese language proficiency to carry out their professional duties are usua..