"Seo Alba Nuadh."
Translation:This is Nova Scotia.
It can do a few different things. Personally I wouldn’t find it helpful to focus on the rules for it at this stage, but every learner is different. The spelling system is extremely regular, far easier than English IMO. There are some good resources if you are the type of person that likes to have every sound broken down too! :)
The difference depends on the vowel sounds around it, and where in the word it occurs (in linguist-speak, we call that the “environment”). So—
-dh in final position (end of a word) —>
- silent after i and o, as in Daibhidh and crodh
- sounds like /g/ after a, as in nuadh
-dh- in medial position—>
- sounds like /y/ when surrounded by i, e (“slender” vowels), as in Nollaig Chridheil.
- silent when surrounded by a, o, u (“broad” vowels), as in adhart
dh- in initial position (beginning of a word) —>
- sounds like /y/ before i and e, as in dhith, Dhè
- sounds like /g/ before a, as in mo dhachaidh
As far as I know, that’s -generally- the case. There may be exceptions that my before-coffee brain isn’t recalling atm.