The two words said by Natasha to The Girls the other day meant 'Come along'. Realistically, I think she'd have said 'Come on' (in a Welsh accent) unless making a concerted effort.
The Mam-gu/Nain Pat routine seems to be another PSA (anyone hear Elis James on yesterday's Today?), because she has lived in Ambridge for about 50 years, and apart from having a brief respite in Prestatyn, and one mention of a relative called Megan, hasn't shown much interest in Wales/Welshness. She also called Olwen Olwyn, which a Welsh-speaker wouldn't do.
The book chosen seemed an odd choice. I'd have wanted books my children to know stories from my own childhood, not translations, thank you very much. We have our own culture.
We don't know where Pat and Natasha are from, but Natasha's accent suggests the South. If she was South Walian, she'd probably mention that children's/learner's books tend to be North Walian dialect.
Same language with the odd word being different, but in speech or written colloquially considerably different.
e.g. Ti moyn dishgled?/Tisho paned?
My translations yesterday were tongue-in-cheek, but you'd get by with them.
Hello - Helo
Goodbye - Ta-ra (or something meaning Cheers!, See ya! etc). Formally, 'Da bo chi/ti'
Yes/No - depends on the question. Ia/Na usually isn't the correct form, and you'd reply with something like 'I am', 'It is', 'He isn't' or 'She was' or whatever depending on context.
Please - Os gwelwch yn dda or Os gweli di'n dda.
Thanks - Diolch
(There isn't a Welsh word for procrastination)