"You are not seeing a bird."
Translation:Chan eil thu a' faicinn eun.
faicinn is a noun meaning seeing as in seeing is important, or act of seeing. Something like
tha thu faicinn… would be a very ungrammatical way to say something like you are an-act-of-seeing.
a’ is a preposition, form of aig meaning at, used before such verbal nouns, so the whole tha thu a’ faicinn means literally you are at seeing and that’s the Gaelic way to express actions that are performed by somebody – somebody is at doing of something (and not just doing something).
Compare archaic or dialectal English a-verbing forms like the times they are a-changin´, I am a-going, soldiers went a-marching, etc. – which I believe come from a similar construction, but the preposition in Old English was different (OEng. on, an, so originally something like I was on going, on marching, on changing). See this English Stackexchange question.
Also compare Icelandic að ‘at’ used in a similar manner, eg. in ég er að brenna húsið þitt ‘I am burning your house’, I believe both English and Icelandic continuous constructions might’ve been borrowed from Celtic languages as they aren’t present in other Germanic languages and both English and Icelandic had a lot of contact with insular Celts.
Oh great, I'm glad someone else mentioned that familiar a-prefixing (still appears in Appalachian English). Very cool to hear this construction is used in Icelandic too, though I'm not sure what makes you say it isn't present in other Germanic languages; German uses "beim" + [gerund] the same way.
I probably should clarify a bit. I didn’t mean that it isn’t possible to say something syntactically similar at all, but that this way of speaking is the mandatory grammatical way of distinguishing progressive continuous actions and non-progressive ones.
In English I burn your house would mean that I do this habitually, once in a while but not necessarily at that exact moment. I am burning your house means I am doing it right now. The same with Icelandic ég brenn… vs ég er að brenna…
But in German you can express both by ich verbrenne dein Haus.
And isn’t the beim + gerund thing a newer development which started as a regionalism? To be fair, I haven’t encountered it before. I’ve heard Dutch has something similar but also not mandatory for progressiveness.
Okay I see what you mean, that even though a parallel construction (along with other options) exists to distinguish the progressive from the habitual, progressive marking itself isn't obligatory in other Germanic languages (except Icelandic, is that right?). Actually, I didn't realise that the so-called Rhinish progressive form of beim/am + gerund, though pretty common now, is frowned upon in Standard German, while the same progressive syntax is considered standard in Dutch and I think Danish.