I wish linguist Annraoi had jumped in to answer this query!

On St Patrick's Day weekend, of all times, we had a introductory Gàidhlig workshop for fluent speakers of Irish Gaelic. Teachers were Iain Mac a' Tailliúir and Beathag Mhuireasdan. Someone asked a similar question - he asked "do you SAY 'stéisean nam busaichean' or '... na-mbusaichean'". A learner who didn't know Irish would be inclined to read and say two distinct words, but the Irish speakers saw the similarity with Irish constructions, for example 'báinne na mbó'. So this was one case where we had more similarity in pronunciation than in spelling; the reverse is often true. I think in this case the Irish is nearer than Sc. Gaelic to older forms.

Also, Irish has more complex rules governing the genitive and more formal use of eclipsis, as Brian has suggested. In Scotland you may hear sounds such as "an gat" (an cat), but you don't have rules such as in Munster and Connacht Irish where cat would have an "urú" after many prepositions: "Tá báinne ag an gcat" (the cat has milk). In Ulster,as in Scotland, we would lenite; e.g., 'ag an chat' except after 'i'/'in' - "Na lig sinn i gcathu" - lead us not into temptation.
But when you see 'na' and eclipsis, it is a genitive - either of a plural noun or of a feminine singular noun. If we wrote 'nan' and 'nam' would we also have to write 'nag' (Cití na gCraobh), and 'nab'(Cúl Taobh na bPéarlaí)?
I hope that does help you understand this difference between our languages (rather than just being confusing!)