Sorley MacLean’s poem Hallaig, a lament to the cleared homesteads of the Isle of Raasay, is his most famous work, lauded by Seamus Heaney, the Irish Nobel laureate whose translation was published in 2002, and the inspiration for countless other poets and songsmiths. Yet few have ever read the poem as MacLean wrote it, or any of the other masterworks from the lyrical canon of Scottish Gaelic literature. Barely 60,000 people speak Gaelic, one of Britain’s fragile minority languages which…