I'm not exactly sure about when to use dw i, i'n and also y'n. I get them 'right' but it's more from guessing rather than knowing.
Dw i = I am
We use it to say your name eg Megan dw i = Megan I am/ I am Megan
We use it with 'eisiau' to want eg Dw i eisiau coffi = I want coffee (I am wanting coffee)
We use it with 'wedi' to talk about something in the past eg Dw i wedi codi = I have got up (I am after getting up)
To connect Dw i to all other verbs we need 'yn'
eg Dw i yn hoffi coffi = I like coffee (I am liking coffee)
Because we have two vowels next to each other here:- Dw I Yn hoffi coffi
We contract this to 'Dw i'n hoffi coffi'
Hope that helps.
Thank you! It's helpful for me to see the literal word-for-word translation as well as the sense of it in English, in order to decipher the grammar. I can memorize phrases and their meaning, like "Dw i eisiau coffi" means "I want coffee," but knowing it translates literally to "I am wanting coffee" helps me understand WHY the sentence is constructed that way.
Question: If "wedi" refers to things in the past, and can translate to "after," then how does the phrase "wedi blino" (I am tired) literally translate?
Be careful about eisiau and angen - they are both nouns, not verb-nouns. They are both used in a way which is similar to using bwyta, canu, etc but there is no yn required to link to them.
(You may occasionally come across them with ag (â, ag - 'with') - Dw i ag eisiau bwyd - I am with a want of some food - I want some food'.)
If you think of verb-nouns such as bwyta, blino, hoffi and so on as being 'eating, tiring, linking' (rather than 'to eat, to tire, to like'), then it may be easier to see how wedi works:
- Dw i wedi blino - I am after tiring - 'I am tired'
- Dw i'n blino - 'I am tiring', 'I am getting/becoming tired'
- Wyau wedi'u ffrio - Eggs after their frying - 'fried eggs'
More explanation of yn and wedi here - https://www.duolingo.com/comment/13844144