"I am not from Inverness."
Translation:Chan eil mi à Inbhir Nis.
No, it is not using the IS of the copula, whether negative or not. So forget Irish constructions around the copula: Is ás Corcaigh mé. Ní ás Baile Atha Cliath mé....agus araile. It is using Tha (think tá without the fada and with lenition) and the negative is Cha also found in Gaedhlig Thír Chonnail from Old Irish nícon, Middle Ir ní co/ní cho, Irish with the exception of Uladh, kept and developed ní, whereas the Northern Gaedheal dropped ní lenited co and the vowel moved to 'a'. So Cha, so, using tá/tha ní/cha sentences it is always, verb first then subject. So in the negative sentence Chan eil mi ..... where ever you are not from. In short, don't think of Irish copula type sentences, use the normal verb 'is' tha/cha in this case and keep the subject by the verb: chan eil mi.... Sorry, for boring you, but I know where you are coming from on this, best of luck. Tá súil agam go dtuigeann tú liom/mé.
Emphasis and contrast and there are some constructions involving 'Is' and 'Cha' which are best looked at in situ. Chan eil mi trang a-nis. I am not busy now. Chan eil mise trang idir a-nis. !I! am not busy at all now! Chan e mise am prìomhaire /Cha mise am prìomhaire : I am not the primeminister.