On grammatical class:

dau
digit/number: hex digit A (decimal 10) [ten].
fei
digit/number: hex digit B (decimal 11) [eleven].
gai
digit/number: hex digit C (decimal 12) [twelve].
jau
digit/number: hex digit D (decimal 13) [thirteen].
rei
digit/number: hex digit E (decimal 14) [fourteen].
vai
digit/number: hex digit F (decimal 15) [fifteen].
xei
digit/number: hex digit E (decimal 14) [fourteen]