I am seeing a weird difference between my grammar book (Irish Grammar book from Nollaig Mac Congáil). In this book - lenition of nouns chapter - he says that ALL nouns (sg., pl., masc. fem.) undergo lenition in few cases including mo, do, a (3rd sg. masc). then I got to "my department" = mo roinne and I realised that according to that it should be mo rhoinne. I do not see any exception he lists to apply.
I assume this is not regional thing?
Certain starting letters do not undergo lenition: r, l,n, sc, sp, st, sm, sf. However, note that, at least with "l", it is lenited in some dialects, but it's never wrriten as "lh"
thanks... I am trying to understand if this is cross referencing issue in the book or just some oversight etc...
just out of curiosity... if it is lenited in some dialects... how is it written then?