"Oh dear, they are shouting."
Translation:Obh obh, tha iad ag èigheachd.
Yes, this is the most common pronunciation, in my experience. Indeed, if you look up èibh or èibheachd at faclair.com it cross-refers you to èigh (which they perversely spell éigh) and then tell you it is pronounced /eːv/. It is not immediately obvious why this word is pronounced this way.
The only etymology I can find to give us a clue is MacBain which says
éigh, a cry, Ir. éigheamh, 0. Ir. egem, Celtic root eig ; Lettic igt. Cf. also Lat. aeger (Stokes, Zim.).
It is not obvious what evidence there is for the claimed Celtic root, but the Old Irish suggests that if it was eig, then the m was added at some stage. They did not always bother with writing the h in the older texts so it may always have been a /v/. Alternatively the m may have changed to mh at some stage as this was quite common. Either way, this seems to tell us where the /v/ comes from. I can only guess that the Gaelic spelling without the mh was because it did not have the mh in all dialects. On the other hand, FGB (Ó Dónaill 1977), a more modern Irish Dictionary than the one MacBain would have used, cross-refers us from éigheamh to éamh. In other words, the Irish have given up on the pretence that there is a gh in the word.
It's not strictly wrong, but it is a question of Duolingo policy (which I do not know). As a general rule you would not put in the san without a good reason, but of course, in these sentences without context it is almost impossible to decide the correct translation. It would be interesting to get a mod's opinion so if someone want to report this omission when they get this sentence we might get a reply.
It was a missed translation in this instance :)
As a general rule you would not put in the san without a good reason, but of course, in these sentences without context it is almost impossible to decide the correct translation.
Indeed. With all that in mind, the emphatic form will always be accepted unless there's a good reason not to, which is very rarely.