Hi all, glad to be on the course and really enjoying it!
Both my self and fiance are struggling with one sentence, now its possible we missed the explanation of which one to use when.
rhaid i mi – I must, I’ve got to
and
mae gen i – I’ve got, I have
Any help would be greatly appreciated
Ben and Shuanagh
This catches a lot of people, and it’s because in English we use ‘got’ and ‘have’ rather liberally when actually they can have different contexts which are reflected in Welsh but not in English.
rhaid i mi - I must, I’ve got to, I have to - as in “there is a compulsion for me to”
mae gen i - I’ve got, I have - as in possession (e.g. I possess a dog)
thank you so much that Siaron clears it up for us both.
I thought that might have been the context , but wasn’t sure.
Thanks
Ben and Shaunagh
@ben-37 hello, I’m having the same problem, I get very confused with these two. Also with a, and when to put in ac? When the sentence came up I’m going to stop speaking Welsh now, I just said sairad cymraeg rhwuan, but it was siarad yn y Gymraeg! I’m quite confused, so any help from anyone will be much appreciated
With a/ac for ‘and’, it’s usually ‘a’ before a consonant and ‘ac’ before a vowel. There are some exceptions which seem to break the rule (e.g. “ac mae”) but this is because the ‘y’ that would have been between ‘ac’ and ‘mae’ is no longer used but its effect remains - but don’t worry about these, you’ll pick them up the more you hear them and it’ll become second nature!
Also, as you go through the course, you’ll often hear the same thing being said in different ways - remember, just because you’ve said something a different way to what’s in the lesson doesn’t necessarily mean it’s wrong, it could be an equally correct way you’ve learnt previously! But SSiW trys to expose you to all different forms so that you’ll recognise them when you hear them even if it’s not the form you choose to use yourself 
PS! The difference between “siarad Cymraeg” and “siarad yn Y Gymraeg” is that the first one is in a more general sense - “to speak Welsh”, whereas the second is in a more specific sense “to speak in Welsh”. E.g “I speak Welsh” = “dwi’n siarad Cymraeg” but “I am speaking in Welsh” = “dwi’n siarad yn y Gymraeg”. The problem as to knowing which occurs because English is lazy and often leaves out the ‘in’ when it should be there! 
@siaronjames hello siaron, Diolch yn fawr for taking the time to reply, and such a detailed answer, I really appreciate it. I’ll keep referring back to your answer, as im sure I’ll make more mistakes. Thank you for the encouragement, and also letting me know I’m not alone and confused with this. Diolch.