language question

I've just been going back over old census records, because I stumbled across a several-greats-uncle's and was reminded that it was recorded here on the census records that the family spoke "Granish" (Gottschee).But I'm looking at the 1930 census record for my gg-grandfather and gg-grandmother, and I'm rather puzzled.Both of them have "Granish" listed as their mother tongues.BUT above this is written "Croatian."(Kind of like they sometimes write "Yugo." in above "Austrian" in the place of origin.)

Now, I am quite confident the family is Slovene, not Croatian.They may have said they were from Austria or Yugoslavia at various times, depending on the current entity in power, but they always said "Slovenian" when asked their ethnicity.I've never heard Granish associated with Croatians, either; it seems to be an American immigrant term for Gottschee German.So why would they have written this in?Did they think they'd misheard, and guess that my gg-grandparents had said "Croatian," because that made sense to them?Or is it possible my gg-grandparents said that Granish and Croatian were both mother tongues for them, so the census-taker wrote down both?

And if that's the case, would it help narrow down the region they came from, at all?