At 12 minutes into the download, we are asked to say:
“I want to know why you want to tell me what you want to know.”
I was quite pleased with myself, because with the help of the pause button, I thought I had it right.
However, both the voices seem to say
I want to know why you want to tell me THE what you want to know.
What’s going on here? It’s an important question, because apparently, if I said it right, I should pour myself a Rum and Shrub
Oh, THAT phrase. 
(I remember cracking up when I first heard it and then laughing even harder at Pol’s rum and shrub comment.)
As far as I know from what I’ve learned of Cornish so far, “an pyth” (literally “the what”) is actually grammatically correct from a Cornish point of view. Cornish sentences don’t always map word-for-word literally onto the English equivalent — the same goes for any other languages, of course. Unfortunately that point isn’t explained in the recording. But I’ve seen “an pyth” in other sentences elsewhere (in textbooks and writings and so on), so I’m pretty sure that genuinely is how it’s used in Cornish.
Enjoy your rum and shrub when you get to it! 
Many thanks Courtenay.
If anyone else know when you should use “the what”, I’d be really grateful to find out.
I have a feeling it’s when the “what” in question is the object of the sentence, rather than the question word that opens it. “What do you want to do?” would be “Pyth a vynn’ta gul?”, whereas “You can’t do what you want to do” would be “Ny yll’ta gul an pyth a vynn’ta gul.” In that second case, the “what” is meaning something definite — “the thing that” (you want to do) — so it takes the definite article in Cornish. I think that’s how it works, but I’m not an expert and would really appreciate it if there’s anyone here with more knowledge of Cornish grammar than I have!!
You might be heading in the right direction, but I’m not sure that’s quite it. Because in lesson three, phrases like “I need to know what you want to do” don’t have “the” in the spoken responses. In this case, it seems to me that “what” is the object of the sentence, as in “I need to know the thing that you want to do.”
Regards
Steve
Hmmm, I’d forgotten that. In that case, I’m really not sure what the proper usage is and would have to defer to someone with a better knowledge of Cornish!
No you were right, I have had it confirmed:
‘Pyth’ is a question word and is used to introduce a question. ‘an pyth’ is not a question word and really means ‘what’ in the sense of 'that which ’ or ’ the thing which’ and so would be more appropriate here. ‘I want to know why you want to tell me that which you want to know’.
So you were right and I’m guessing that in lesson three it’s part of a question. Hopefully this would be a distinction that becomes more natural with use.
However, I now have another problem. At around 31:45 in the download of lesson four we are asked to say “I can’t understand the answer yet.” Once again, I thought I had the answer correct, only to hear an extra word before the final hwath, It sounds like “na” but only being said once and very briefly I’m not totally sure. I looked up na in an online dictionary, but what was shown did not seem to apply to this context.
Any help would be very gratefully received.
BTW I have only just stumbled across this second confusion, as I have only now reached the end of lesson four. I don’t learn language quickly and I don’t manage to swallow a whole SSiC lesson in one go. I’m always amazed at the speed so people devour them.
I remember being confused about the “na hwath” too and I’m afraid I’ve never been able to find an explanation for that one, as it only occurs a couple of times in the SSi recordings and I haven’t found it in any textbooks. It seems to be a use of the double negative — “Ny allav vy konvedhes an gorthyp na hwath” meaning literally “I can’t understand the answer not yet.” Cornish does use double negatives, as do many other languages (and English did originally too). But I don’t know if the double negative is necessary when making a negative sentence with “hwath”, or if it’s optional, or if what’s on the recording is a mistake — there are a few mistakes in a handful of the 10 lessons we have so far. Sorry I can’t help more than that.
There are weekly Cornish lessons near Penzance, which I intend to go to when we are finally clear of the novel corona virus restrictions. I’ll find out then and post back here. Unless of course someone else knows the answer.
Thank you so much for all your help.
You’re welcome, Steve. I hope the current situation clears up reasonably soon and you can get to the classes — it is a huge help to have teachers and other students to learn with and interact with.
Oll an gwella (all the best) 
Hello All, Has anyone come to the understanding of why “na” before yet as spoken about in lesson 4? The phrase is I can’t understand the answer yet and in the Cornish they throw a “na” before the yet. Sorry I am late the the game though just getting started here and was swimming along until lesson 4 with the rub and shrub and then the Na before yet.
It’s all fun though!
Thanks!
I’m afraid I haven’t found any explanations of that… like I said before, I think it must be an optional double negative, which is grammatically acceptable in Cornish (and a lot of languages other than English!). Unfortunately, as they only do it two or three times in these lessons and there’s no explanation of it — and in other negative statements involving “hwath”, they don’t include the “na” — it doesn’t really make sense. There are several errors or confusing bits throughout the lessons, not many, but they do make it a bit harder. I’d go with whichever form they use most often, which is “hwath” without the “na” when making a negative statement (“Ny allav vy konvedhes an gorthyp hwath”). Other Cornish speakers will understand it either way.
“Rum and shrub”, if you didn’t know, is a traditional Cornish and West Country drink — rum with a fruit cordial added (more info from Wikipedia). I’ve never tried it, so can’t comment on whether or not it enhances one’s Cornish speaking ability! 
Thanks Courtenay! Appreciate the feedback and had a nice chuckle at the end! 
Doesn’t it mean ‘that answer’ - i.e. an gorthyp 'na?
Yes, it could mean that, technically, but the line given is “I can’t understand the answer yet” — I don’t think the lessons have included “an ____ na” for “that ____” at this stage. Also, it’s a while since I last heard it, but I’m pretty sure the speakers both pause slightly before the “na”, so that it comes across as “Ny allav vy konvedhes an gorthyp… na hwath” rather than “Ny allav vy konvedhes an gorthyp na… hwath.” But that is a possible ambiguity there, good point.
(Incidentally, one thing that bugs me about SSi is overuse of the pronoun suffixes (enclitics) — it doesn’t need to be “ny allav vy” or “da yw genev vy” unless you’re emphasising “I can’t”, “I like” and so on. “Ny allav” and “da yw genev” are absolutely fine on their own, as they’re already indicating first person singular. The “vy” is redundant unless there’s some need to emphasise oneself — and throwing in the enclitics like that when you don’t need them is pretty sloppy Cornish. But the course overall is so good and so much fun — it definitely got me speaking and thinking in Cornish faster than anything else has! — that I’m not going to complain too much. )