Can someone please tell me if this is right before I go ahead and post my reply on Reddit?
So I wrote all this and then realized that it might be way too much for a complete beginner. As someone on another forum said, if this is the first time you have looked at Welsh, there is no grammar book on earth that will not put you off. Grammar is definitely not the right way to start learning Welsh. Have you heard of SaySomethinginWelsh? If not, they’re the first place you should start before looking in depth at grammar.
Not an expert, but I took a Welsh course last summer that had some useful materials.
"Just like English, most Welsh sentences use the periphrastic (roundabout) construction, so instead of saying “he sings right now,” we usually say “he is singing right now.” The Welsh form of “is singing” is the verb-noun (berfenw), the dictionary form of the verb. Canu can be “to sing” (verb) or “singing” (noun), which is why it’s called a verb-noun. Think of yn as a giant hook: if a Welsh sentence has a predicate, it requires yn or something equivalent to hang it on. Yn causes no mutations in verbs.
The yn isn’t translated, but you can think of it as “in the process of / engaged in” if you need a meaning for it. When you stress the verb (he is singing), in Welsh you’d stress the yn (mae e yn canu). Other prepositions can be used in place of yn, with different meanings."
-Cymdeithas Madog, Cwrs Cymraeg 2015, Lefel 2
Let’s look at some of your examples:
(I’m used to the spelling “Dw i eisiau”, so I’m going to use that one or else it will just look wrong to me.) The standard way of using eisiau would be like “Mae eisiau [rhywbeth] arni i”, or “I want [something].” It literally translates as “there is a want of [something] upon me.” Angen would be used in much the same way. Kinda weird, right? According to the same source as above,
“Prepositions are used to convey all sorts of transitory states where English uses a verb.”
Talking about eisiau and angen,
"Both of these words can be made into semi-verbs (under the influence of English):
Dw i eisiau [rhywbeth]. Note that there is no yn!"
It’s probably safe to assume that the lack of yn has something to do with the fact that it’s not really a proper Welsh sentence constuction.
Same as above.
This is one that I’m not sure about, since newydd isn’t exactly a preposition. In this case, newydd is an adverb meaning “just”, or literally “newly.”
- Dw i wedi (anghofio/dysgu…)
This is an example of using a preposition instead of yn. Wedi is a preposition meaning “after.” So, when you say “dw i wedi anghofio” to mean “I have forgotten”, what you’re literally saying is “I am after forgetting.”
- Dw i wedi bod yn (dysgu/siarad…)
There is no yn after wedi, as in the previous example. I think the yn after bod in this case is the same usage as the yn in “Dw i’n dysgu.” After all, the dw in dw i’n comes from conjugating the verb bod.