How do I Say and Write
"Twenty" in Japanese?

Pronunciation : Twen"ty
Part of Speech : a.
Etymology : [OE. twenty, AS. tw, twentig; akin to OFris. twintich, OS. tw, D. & LG. twintig, OHG. zweinzug, G. zwanzig, Goth. twai tigjis; that is, two tens. See Twain, Two, and Ten.]
Definition : 1. One more that nineteen; twice; as, twenty men.

2. An indefinite number more or less that twenty. Shak. Maximilian, upon twenty respects, could not have been the man. Bacon.
Source : Webster's Unabridged Dictionary, 1913

Pronunciation : Twen"ty
Part of Speech : n.;
Definition : 1. The number next following nineteen; the sum of twelve and eight, or twice ten; twenty units or objects; a score.

2. A symbol representing twenty units, as 20, or xx.

pl. Twenties (.
Source : Webster's Unabridged Dictionary, 1913