"When do you get paid?"
Translation:Pryd wyt ti'n cael dy dalu?
Generally words like 'Pryd', 'Ble' and 'Sut' (when, where and how) don't require the question form of the verb to follow them.
So in this example the best answer should be 'Pryd rwyt ti'n cael dy dalu'
Some dialects tend to use the question form so the 'r' is dropped from 'rwyt'.
When this sentence was entered the less 'correct' version was used, the more correct version was subsequently added as an alternative.
This is something to correct for the revised course.
That's because you can't use the final pronoun, i.e. di, in passive constructions like these - it's only ever cael dy dalu, never *cael dy dalu di. This is the same for other persons too, e.g. Pryd dw i'n cael fy nhalu?, Pryd mae hi'n cael ei thalu?, Pryd dych chi'n cael eich talu? "When do I / does she / do you get paid?".