Dylen i

Bit confused re Dylen i
When you say “I think that”, it usually is
Dwin meddwl bod….
But “ I think that I should “ the bod seems to disappear to what sounds like “Dwin meddwl y dylen I”.Why isn’t it Dwin meddwl bo dylen I?

Can anyone explain please?
Diolch yn fawr

Well, the core of the problem is that there is more than one word for “that” in Welsh (And the word “that” has multiple meanings and uses in English, to make things more interesting!)
The “bod” construction is used when the sub-clause contains an unconjugated verbnoun, for example
I think that you want to drink beer - Dw i’n meddwl bo’ti’n moyn yfed cwrw.
But dylen i is itself a conjugated form, so here the subclause is introduced by y (and is often left out in speech entirely)
I think that I should go. - Dw i’n meddwl (y) dylen i fynd.


Diolch Hendrik