In level 1 13 this sentence in the notes says
Oedd yr hen ddyn yn moyd dweud rhywbeth wrrtha i neithiwr
The Old man wanted to tell me something last night.
In challenge 14
*Dwedodd y fenyw *ifanc yn yr dafarn neithiwr bod hi’n moyn siarad gyda ti
The young woman in the pub last night said that she wants to speak with you
Cant get my head round why The old man is Oedd, but The young woman is Dwedodd?
Unless it makes sense I have trouble remembering which to use
Jackie
these are just two ways of expressing the past tense -
roedd yr hen ddyn yn moyn dweud - the old man wanted to tell (the wanting being something that occurred over time and not a single action)
dwedodd y fenw ifanc … bod hi’n moyn - the young woman said that she wanted (the saying being the single, completed action)
Does that help?
You are comparing different verbs and different tenses, which might be why it doesn’t register. A literal but not English translation might help you:
Was the old man wanting to tell me something last night.
Said the young woman in the pub last night (that) be she wanting to speak with you.
A bit of a cross-post with @siaronjames…
I do have trouble distinguishing between the two but I can just about get what your saying so will carry on regardless.
Thanks both for quick reply @siaronjames @SteakAndEggs
Challenge 14 is a cruel one…
This is another ‘on the button’ question - well done 
This one tripped me up too.
Welsh is different to English in this respect.
There are a group of verbs which use the ‘was’ tense to create the past tense. You will get to know them very quickly but they tend to be verbs which imply a state of mind, for example…
Meddwl - to think
Gwybod- to know (something)
Nabod- to know (someone)
Eisiau or moyn- to want
Hoffi - to like
Gobeithio - to hope
Caru- to love
Casau- to hate
Swnio- to sound
They are called stative verbs.
Rich 
I just got excited…only one of those words was new to me (the last one). I am not conversant, mind you; but by jingo I knew them 
A good rule of thumb for native/fluent English speakers is that the verbs that sound weird in the continuous present in English (**I am sounding, **I am hating, **I am loving, **I am wanting, **I am knowing instead of ‘I know’, ‘I want’, ‘I love’ etc.) are mostly the same ones that use ‘was’ in the past in Welsh. I think it’s not quite perfect, but it does make it easier to get a feel for it.
Yes! That’s a good one.
I don’t really understand what you mean by this. I was under the impression that you could use this form with any verb?
O’n i’n trio dweud…
Oedd hi’n ysgrifennu…
I think I’ve misunderstood one of the finer (or perhaps not!) points of grammar here.
Hi Stephen,
Yes that’s right - you can use the was form on any verb.
The slight difference between the two languages is that to say ‘I thought’ in Welsh (or any of the stative verbs above) you’d say ‘I was thinking’.
‘I was thinking’ = ‘I thought’
So it’s not that there is a restriction on the ‘was’ tense. It’s that you wouldn’t put a past tense ending on these types of verb or use a past tense verb before it to create ‘I did think/ I thought ‘ (in normal usage) because the ‘was’ tense covers that.
Quite tricky to describe in fact!..does that make any sense?
Rich
I’m not quite sure. Do you mean that for these verbs you’d more likely use “Roedd” (etc) than use gwneud to form the preterite?
i.e. “O’n i’n meddwl…” rather than “Wnes i feddwl…”?
Your example is exactly right - roedd gives the past tense of these verbs - and not gwneud or an ending.
Rich
It is. Sorry… 
Just blame me, and move on - some bits will have stuck more than you currently realise…
I’m probably being slow but I thought meddwl became meddylais i.
It’s amazing what you can find on this forum - here is a ruling from the great man himself - it is ‘possible but not natural Welsh’ - see below.
[ edit: BTW I meant this totally positively - I hope it didn’t come over in any other way - I thought this was a great question, Rich ]
Hopefully helpful is another approach that works for me -
As with a first language, you can ease off on soaking in the grammar rules just for now and just copy speaking the way that things are said in the Challenges, or wherever you here them. That way you can get the feel of which words attract which constructions.
How lovely…perfect 
McDonald’s would disagree with Gareth there though… “I’m loving it” 
