What the plural of sgian dubh?

[OC Richard]

In gaelic, the adjective does not mutate.

Thanks!

So sginean-dubh?

I take it that the noun does not have initial mutation in this case?

[Calgacus]

Thanks!

So sginean-dubh?

I take it that the noun does not have initial mutation in this case?

You've reached the limit of my knowledge of Gaelic, but going from Nathan's Wikipedia quote above...

The plural is most commonly sgian-dubhs (in its various spellings) but sgians-dubh is also occasionally encountered. The proper Gaelic plural forms sg(e)inean-dubh or sgianan-dubh are only rarely encountered in English usage.

...you appear to have a couple of choices.

[OC Richard]

It's interesting that the singular sgian has broad n but the plural sginean has slender n, meaning (as it seems to me) what a linguist would call a y-offglide to the n in sginean.

On many Gaelic nouns an 'i' is inserted between the vowel and the final consonant to create the plural, making the final consonant slender (marbh v mairbh) and it's interesting that sgian follows this pattern.