Early Quenya
yundóre
cardinal. billion
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
yundóre
cardinal. billion
The manuscript version of the Early Qenya Grammar (EQG) of the 1920s had ᴱQ. yundóra “two million” (PE14/50), but in the typescript version this became ᴱQ. yundóre “billion” (PE14/83), a combination of ᴱQ. yúyo “two” and the “-illion” suffix ᴱQ. -(n)dóre.
Neo-Quenya: I would retain ᴺQ. yundórë “billion” for purposes of Neo-Quenya, as we have no better alternatives. Compare later Q. yucainen “twenty” = “✱double ten”.