Yeah @Kimberley there is a Cymraeg option on most of the ones I've seen in Wales.
The machines used to say a lot more than they do now, they'd match all of the English phrases (Put your bag on the scale, Search for items or have a browse, scan your clubcard, thanks for shopping at Tesco) etc.
However, a recent software update has pretty much rendered them mute, with the only thing they now say being
"Sganiwch eich cerdyn clubcard i ennill pointiau clubcard" Which my rudimentary Welsh translates something like "Scan your clubcard to earn Clubcard points".
Bit of pot luck, but sometimes it does also tell you to put your bag on the scales, but I've found this only works sometimes.
I love nothing more than complaining, so I have lodged a complaint with Tesco until we get all of our old phrases back!