S’mae Justin?
I believe both are fine. When bod is being used, the past tense is being implied from the first part of the sentence (ddudodd hi, est ti, ayyb). However, my belief is based solely on expeience from working through the SSiW courses and from talking to Welsh speakers; I cannot claim to have any knowledge of the grammar at work here…
Hwyl,
Stu
Yeah, this is an idiosyncracy of Welsh - maybe someone can give a detailed grammatical explanation, but broadly speaking ‘bod’ kind of inherits the tense that has been set earlier in the phrase - which means that if you’re using ‘bod’, we don’t really have a way to distinguish between ‘she told us that there was no need’ and ‘she told us that there is no need’.
As for ‘ddudodd hi doedd dim angen’ - I wouldn’t be surprised if it was, technically, not grammatically correct (although grammar really isn’t my thing, so that’s not a statement of fact!) - if it is, though, it would certainly not interrupt understanding in any way 
Ah, grammar! The ol’ “Syntax of Welsh” has the following to say about this topic, in Section 3.3, Bod-clauses: finite clauses with the infinitive bod, subsection 3.3.1, The distribution of bod:
“…in affirmative and declarative contexts, embedded clauses cannot contain the present tense of bod…” The example given is “Mae Aled yn credu mae Elen yn darllen y llyfr” - this is not grammatical, it says, and should be “Mae Aled yn credu bod Elen yn darllen y llyfr”, as we all know. Then it says: “…it is also common for speakers to disallow imperfected tensed forms of bod in these contexts too, though various idiolects permit this…”
So we have “Mae Aled yn credu bod Elen yn darllen y llyfr” and “Mae Aled yn credu roedd Elen yn darllen y llyfr”
In other words, both roedd and bod are grammatically correct in your question. And Eirwen, of course
There is not much explanation, except that “the infinitival form, bod, translates either present and imperfect tense in these contexts”.
I have no idea if this is any clearer now, probably not, but my take-away is that for the past, both bod itself and past versions of bod (roedd, roeddet, roeddwn, etc) are acceptable use, but bod works for the present and the past.
Also “important” 
(when discussing grammar stuff like this) to remember that “bod” is not the “present” tense of “to be”, it’s the verb-noun, “a being”, (or rather something essentially untranslatable - [ as indeed most things are perfectly!])
Ydw/dw/w I
Wyt ti/ 'ti
Mae fe or sydd/sy or ydyw/ydy/yw
Ydyn ni /'yn ni
Ydych/ych chi
Ydyn nhw/ yn nhw
Etcetera, etcetera, are the present tenses of the verb “to be”.
“Bod” doesn’t really have a “tense”, past, present or future as it were.
And Welsh treats “that” clauses in a different way to English in many ways.
[Including as to whether in a sentence like “Heironomous told me (that) he was sitting on a giant mushroom”, the second part of the sentence “he was sitting…” has to always be treated In other languages as being in the past tense, as it was in the present when Hieronomous told you… I shall stop there! [[edit- this only possibly comes into play when considering whether to use “bod”… oh, I should have stopped!]]]
But basically, just roll with it, and the fundamental answer to “why is it different to English?” is “because it isn’t English.”
But going back to the original post, and remembering other stuff you have posted, I would say that though normally what is “correct” Welsh has to come with an enormous number of important caveats, the fact you have a wife whose first language is Welsh, that in your case, those are two pretty much inarguable reasons as to why what she says are the correct things to use in your case!
[quote=“louis, post:4, topic:1823”]
“…in affirmative and declarative contexts, embedded clauses cannot contain the present tense of bod…”[/quote]
Diolch, Louis. Isn’t that gloriously quirky?
Oh, good - that would explain why it sounded as though it might not be technically correct for me. Er, that is, if I’m anywhere near understanding what ‘imperfected tensed forms’ means!
If anyone at all understands that, I’m a Dutchman! But your idiolect is not wholly idiosyncratic, by the sounds of it
I did, so you must be.
That’s the first time I’ve ever come across the phrase “imperfected tensed forms”, but it’s pretty clear it just means forms in the imperfect tense, isn’t it?
I mean, I probably would have written (had I been inclined to write it at all!) “disallow forms of bod in the imperfect tense…”, but is the other form used really comparatively that opaque?
And as for “…in affirmative and declarative contexts, embedded clauses cannot contain the present tense of bod…”,
Surely that is an effective and concise way of saying it, if the words within it have been defined?
Apologies, that is my typo; the actual text is “…disallow imperfect tensed forms…” - and you are quite correct in your interpretation. As to the definition of the words in the last passage, I am afraid that there is no glossary in the book, which (the book, that is), according to its preface, “…will be welcomed by theoretical syntacticians, typologists, historical linguists and Celticists alike.” I assume that the terminology in the book is clear to that sort of people. 
I don’t even know what a typologist is, mind.
Oh, words can be defined either in the book or, so you say, outside it if that is expected of the target audience.
I bought a book once on Welsh syntax (by accident!) which was aimed at students of linguistics, and I can’t make head nor tail of it - but I wouldn’t expect to!
But context and re-reading, learning how the words are used can make stuff like that clearer, as you know!
It’s only the word “declarative” there which is a bit odd, surely?
And looking it up, in another book, on decent sites on the Internet, or (oh, old fashioned idea!) in a good dictionary, you find out it apparently means, in gramatical terms, a statement which makes a declaration- which gives information, the most common form of sentence- a simple statement which is not a question, an order or an exclamation. (Apparently maybe! )
I mean, sometimes you have to- sometimes you ought to - look words up in a dictionary. Sometimes you have to re-read and consider stuff. (Not saying people don’t, just saying sometimes we have to!)
In my opinion, of course, and I know it’s even the case that no-one else has said anything to the contrary!
Louis,
is the “tensed” correct? Because if so, that’s a rather awkward / ugly phrase, assuming the author was a native English speaker. I know you can make a verb out of almost any noun (Shakespeare did, so it’s ok), I doubt if many of us go round using the verb “to tense” very often, although perhaps linguists (i.e. linguistics experts) do.
Because I am very interested in learning languages, I used to think I would be interested in and moderately good at linguistics. However, any attempts by me to study it have soon ended in failure and loss of the will to live. (Perhaps because the text books use phrases like “disallow imperfect tensed forms.”. It’s a genuine shame. This should be an interesting and captivating subject.
Yes Mike, “tensed” is there in the text, and yes, the authors (Robert Borsley, Maggie Tallerman and David Willis) are native English speakers, all theoretical linguists at various English universities. This book is most definitely a linguistic/scientific piece of work, and having become stuck in its morass of dense, turgid prose on numerous occasions, I can attest that the book’s authors make no concessions to its accessibility by the general public.
The book is most certainly not written to help anyone learn Welsh, but I myself find it interesting to read how Welsh is treated as a subject of linguistic investigation - call me crazy…
I think my fairy godmother waved her wand and put that phrase ‘‘imperfect tensed forms allowed in some dialects’’ in there to make everyone a winner - and save Eirwen’s reputation!!
No you certainly aren’t crazy Louis, because, this subject ought to be fascinating. It’s a pity it can’t be made more accessible though.
And now I have to contradict myself (just for a change 
) as I’ve realised that we (civilians) do use the verb “to tense”, e.g. when we say “I tensed up” (i.e. became tense, physically), although it’s obviously not the same as the linguistic usage.
No this is not sufficient evidence of your “craziness”, Louis. I’ve always had a lay interest in linguistics since my university days in the 60s when you couldn’t attend any cool parties without being to discuss Noam Chomsky (supposedly the daddy of it all) with an air of plausible knowledge. I’ve still got “Problems for Knowledge & Freedom” (?) but it’s a bit like Hawkins “Brief History of Time” which also spent a brief time on my coffee table.
Name dropping alert: I had the pleasure of meeting David Crystal in Reading when I was a joint supervisor of a project with our Speech Pathology department.
Current state of my lingistics knowledge - as always - Llareggub 
Ah now, David Crystal. I’m sure he could write confusing books if he wished to, but he seems to prefer to make them understandable, enjoyable, and still erudite.
I am suitably envious -David Crystal! - his Cambridge Encyclopedia of Language is on my reading queue, and yes @mikeellwood, I agree, his writing is very accessible
I hope I didn’t imply that David Crystal was inaccessible. On the contrary, he was clear, helpful and charming. We visited him with a doctorate student in connection with her research into monotony as an early indicator of Parkinson’s disease. My input as a physicist was as the knob-twiddler and data processor of the gadget she was using to “diagnose” monotony - a laryngograph.
Not at all Hew.
He seems to be a man of many parts, and among other things is active in the “Shakespeare in the original pronunciation” world; fascinating stuff and makes it come alive a bit more when e.g. you hear it rhyming as originally intended.
“Huw” actually, Mike. My forum name is a bit of a red herring and was based on the fact that I used to do a lot of work with the European Commission. My “pun” has misled many others.
Apologies for side-tracking this topic. I seem to be much more prone to doing it than I was on the old, old forum.