We want to compare the IRT-estimated ability vs. age plots for each language model to make sure that nothing is funky with the fits. (Particularly since Danish and Norwegian comprehension item parameters have shifted distributions compared to the other languages.)

Overall Ability Distributions

The ability distributions per language greatly overlap.

Comprehension Ability vs. Age

Correlation of comprehension ability and age: r(16190) = .54, p < .001

## `geom_smooth()` using formula 'y ~ x'

Production Ability vs. Age

Correlation of production ability and age: r(13668) = .62, p < .001

## `geom_smooth()` using formula 'y ~ x'

Production vs. Comprehension Ability

Correlation of comprehension ability and production ability: r(13467) = .43, p < .001.