"Do you have two sisters?"
Translation:A bheil dà phiuthar agad?
In Gaelic, plurals don't start until three. So two still takes the singular. As does twenty, for some reason.
It's explained in the tips and hints for the "Numbers" skill. If you can't easily access these notes because you're on a phone or something, the whole lot is collected on one page here. https://duome.eu/tips/en/gd
However the notes for this very section (Family) explain that strictly speaking, in counting people you should use “dithis” for 2, followed by the plural. In other words, in this case “dithis pheathraichean”. It seem bizarre that DL rejects it here. If it is considered outdated, why mention it in the notes?