[downsplat]

That's more or less how it works in English too... is it really that bad? Spanish and French also have special words for the teens, it's quite common in Europe and I've never heard of it being that difficult to learn.

Some languages have it much worse... I think Hindi is pretty irregular up to 100 .

[samus]

English has special words until twelve. Until nineteen it follows a pattern. The few exceptions to that pattern also apply to the multiples of ten. twelve-twenty, thirteen-thirty, fifteen-fifty, and that's it. It could be much, much worse.

[boxed]

Twenty is special. That destroys the entire 20-29 series.

[anthk]

In Spanish, just 11 to 15.

[FeteCommuniste]

In Greek only 11 and 12 are different, with 12 (δώδεκα = dodeka) being obvious to anyone who learned geometry.