Level 2/ 1 eich or dy?

In lesson 1 of level 2 I don’t get:
Wyt ti isio i mi wylio eich plant.
Shouldn’t this be
Dych chi isio…
…dy blant?

This is where the lack of distinction between a singular and a plural ‘you’/‘your’ in English can throw things a bit.

Yes, it could be Dych chi isio + eich plant … this would be if you were addressing more than one parent (therefore using both a plural ‘you’ and a plural ‘your’) or being very formal.

It could also be Wyt ti isio + dy plant … this would be if you were addressing just one parent (using both a singular ‘you’ and a singular ‘your’)

But! you could also be addressing just one parent with a singular ‘you’ (wyt ti) but referring to the children of both parents with a plural ‘your’ (eich).

All those variations would make sense in those contexts, however, addressing both parents in the plural (dych chi) and then using only a singular ‘your’ (dy) wouldn’t make sense grammatically.