"You must think in Welsh."
Translation:Mae rhaid i chi feddwl yn Gymraeg.
I ran out of hearts because it would not allow "Mae rhaid i ti feddwl yn Gymraeg", the familiar equivalent. O diar. I'm going to have a coffee now in my Welsh mug.
I have never heard of chdi being used in North Wales, which is where I have lived all my life. It's either chi - for formal or group use, or ti - for informal. At least that's what I know of. Is chdi used in the more traditional parts of North Wales?
Some north Walians use it, others don't. It's often an alternative to ti but some maintain a three-way distinction, with chdi, ti and chi all having slightly different meanings. Pretty cool!
It's because yn Gymraeg is an abbreviation of yn y Gymraeg "in the Welsh language". The y "the" is usually dropped, leaving yn Gymraeg.
All this time I have believed that Gymraeg pertained to things Welsh and Cymraeg pertained to the Welsh language. Have I had it wrong all this time? It's worked for me so far.