NASA Astronaut Corps their home agency but trained with and serve alongside their NASA counterparts. International astronauts, Payload Specialists, and Spaceflight Participants are not considered members of the NASA Astronaut Corps. The term "Astronaut Candidate" (informally "ASCAN") refers to individuals who have been selected by NASA as candidates for the NASA Astronaut Corps and are currently undergoing a candidacy training program at the Johnson Space Center. The most recent class of Astronaut Candidates was selected in 2017 after receiving more than 18,300 applications. Upon completion of a two-year training program, they will be promoted to the rank of Astronaut. Selection as an Astronaut
Chinese as a foreign language neutral (轻声，denoted as no-mark in Pinyin) although the official name of the tones is Four Tones. Many other Chinese dialects have more, for example, Cantonese has six (often numbered as nine, but three are duplicates). In most Western languages, tones are only used to express emphasis or emotion, not to distinguish meanings as in Chinese. A French Jesuit, in a letter, relates how the Chinese tones cause a problem for understanding: Moser also stated that tones were a contributing factor to the difficulty of learning Chinese, partly because it is difficult for non-native learners to know how to convey emotion