I recently created a web app called Kazu which aims to help speakers of Japanese and English learn to read numbers in both languages.
I found a web page which said that 'for numbers over 1万
, "1000" is read as いっせん
.
So, to be consistent with 一千万{いっせんまん}
, I used 一千億{いっせんおく}
and 一千兆{いっせんちょう}
.
I'm also using いっせん
where 1000 appears in other parts of the number, so 1万1000
comes up as いちまん いっせん
.
I've tried to clarify with 2 native speakers whether these are the best choice for the app, and both of them said "it depends on the person", but they also said せんおく
sounds better than いっせんおく
— except when there's a counter word like 円
or 個
.
Now I'm really confused. If you had to choose one "best" pronunciation for 1000億
and 1000兆
, as in my situation, what would they be? What would you say for numbers like 1万1000
? Should I change my decision?