"Thig a-steach Oighrig."
Translation:Come in Effie.
Are people still forced to 'anglicise' their name? I would find this all much easier if Ealasaid was just Ealasaid, and Oighrig was Oighrig, and not have to remember which anglicised name was assigned to a Gaelic name. If someone introduced themself to me as Oighrig, why would I then call them Effie? I've ended up with a (pointless?) table to summarise them all, but if I was introduced to someone as Elizabeth, I wouldn't call them Ealasaid, and vice versa.
Definitely not, but the situation is now asymetrical. People with Gaelic names tend to keep them but people with English names with a related Gaelic name tend to change them (like I did). I suspect those with arbitrary equivalents like Effie may be less inclined to. I'm not sure because a lot of these names are quite old fashioned in English and I have never actually met an Effie.
See here for discussion of practice in the media.
It has nothing to do with Oighrig except that there was a time when Gaelic was banned and people with Gaelic names were forced to adopt English names, especially at school, on a fairly arbitrary basis. Luckily those times are gone and if you are called Oighrig you may continue to do so, without fear of punishment at school.
They just looked around wildly for any English name that did not already map to a Gaelic one in common use. Sometimes there was a vague similarity in sound, as in Sarah for Sorcha, and sometimes there was a vague similarity in meaning, as in Claire, also for Sorcha, because Gaelic sorcha and French claire mean the same thing ('bright', 'light').
It happened like this because the people who did it had absolutely no respect for the language, the culture or the people. An eminent linguist, Otto Jespersen, summed up the sentiment quite well in 1905 when he said
We now see why so few Celtic words were taken over into English. There was nothing to induce the ruling classes to learn the language of the inferior natives; it could never be fashionable for them to show an acquaintance with that despised tongue by using now and then a Celtic word. On the other hand the Celt would have to learn the language of his masters, and learn it well; he could not think of addressing his superiors in his own unintelligible gibberish, and if the first generation did not learn good English, the second or third would, while the influence they themselves exercised on English would be infinitesimal.
The only thing we can be thankful for was that this attempt at cultural genocide was not quite as profound, long-lasting or successful as what white people did to the native Americans or the Australian Aborigines until 1970.
I did an Ngram using all the spelling variants listed in Wikipedia for Erica and Euphemia in British English, and they about are even until 1900 when Erica takes the lead, exploding in the 21st century. The explosion begins a bit earlier (about 1970) in the US.
However, this data is not specifically for Scotland. My experience of living in Scotland and reading all sorts of things about the past is that Eupehemia was very popular, probably starting in the enlightenment, amongst educated people, and that Effie was, until quite recently at least, popular amongst Gaels when speaking English, probably precisely because it was the official translation of Oighlig. But I don't think I have ever heard of Erica here. I guess is it usually used as a female form of Eric, which itself is a name more popular in England and used extensively by Norse royalty in the past, but not, so far as I am aware, in Scotland.
Erica is also the Latin for 'heather' but flower names were generally considered 'working class' so it would be unusual to find one in its Latin form.