Saving a language is one thing, but I'm saddened by Scotland going Gaelic

My new passport arrived the other day: my pasbort, my cead-siubhail. Inspecting it, I discovered myself to be a citizen of Teyrnas Gyfunol Prydain Fawr a Gogledd Iwerddon as well as of Rioghachd Aonaichte Bhreatainn is Eireann a Tuath – what tricky words these are to type – which is how the United Kingdom translates into Welsh and Scottish Gaelic on the passport's title page (the days of the French alternative are long gone). Anyone who lives in a big British city got used long ago to the idea of English as one local language among many: the opening hours of the radiotherapy unit posted in Punjabi, Turkish, Somali and Bengali, the mobile callers on the bus who speak to fellow migrants from Tirana, Vilnius, Lagos and Kraków, or to their families who still live there. But the Welsh and Gaelic phrases on the passport are surprising. They don't answer to this present Britain. They exist in a more historical landscape, to redress old rural grievances rather than to express new metropolitan demands.

The European charter for regional or minority languages calls them "autochthonous", which strictly means native, but now also carries the suggestion of a language that's been displaced in importance by a more popular newcomer. Within the United Kingdom, the charter also recognises Cornish, Scots (aka Lallans), Irish Gaelic and Ulster Scots. The charter, which the UK ratified in 2001, asks that all be encouraged to survive. Two of them, Scots and Ulster Scots (aka Ullans), would be contested as languages separate from English or each other, and some might argue that Ullans was invented for purely political reasons, as a Protestant counterweight to the Irish Gaelic that was recognised by Northern Ireland's peace agreement. But then most language lobbies are as much political as cultural: at their most powerful, they have helped break up polyglot empires and kingdoms, and redrawn the boundaries of nation states.

Of this particular kingdom's minority languages, I can understand Scots and Ulster Scots – if languages, and not dialects, are what they are. With a little practice and recollection, remembering the words and expressions my parents and grandparents used and looking up others in a dictionary, I might even be able to speak the first, while a reasonable impersonation of Ian Paisley would bring me within shouting reach of the second. All the Celtic languages are a mystery. How far would I need to reach back to discover an ancestor who spoke Gaelic? Perhaps to what in England would be called the Chaucerian era, perhaps to never: Scotland has a complicated and sometimes uncertain linguistic story that includes Norse and the Northumbrian variant of Old English in the east, as well as the Gaelic that arrived with Irish migrants in the south-west, all of them eventually replacing a form of Celtic or Brittonic language that still survives in contemporary Welsh.

For five or six hundred years Gaelic did well and expanded aggressively across most of Scotland, but it began to lose the competition with Scots-English as early as the 13th century, and then began its long retreat to the Highlands. By 1755, Gaelic speakers numbered only 23% of the Scottish population, which had shrunk by 1901 to 4.5% and 100 years later to 1.2%. Today about 60,000 people speak it, most of them concentrated in the Western Isles, and all of them bilingual in English. Multiply that figure by five to get the number of Cantonese speakers in the UK, by 10 to reach Punjabi, by 20 to those who use Bengali, Urdu and Sylheti. These are conservative estimates for the UK as a whole, and take no account of many other migrant languages, including those from eastern Europe; but even if the comparison is confined to Scotland, it looks likely that the number of citizens who speak South Asian languages at least equal those who speak Gaelic. And yet, unlike Gaelic and Welsh, none of them has the protection of parliamentary acts and an expanding bureaucracy, nor has any been rewarded by a publicly subsidised television channel of its own.

The Gaelic lobbyist has a reasonable argument. Whatever happens in Britain, these other languages will continue to thrive in their original homelands. They aren't in danger of extinction, whereas, in the words of John Angus Mackay, the chief executive of the Gaelic development board (Bòrd na Gàidhlig): "If Gaelic is to survive, it will only survive in Scotland." But cultural preservation comes at an expense. The Scottish Review, a brave and lively online magazine, recently calculated that the annual £17m cost of the Gaelic channel, BBC Alba, meant that almost 30% of BBC Scotland's programme budget was devoted to slightly more than 1% of the Scottish population. People grumble about the BBC Scotland's "Teuchter [Highland] mafia" – four of its eight senior managers are Gaelic speakers – but the resentment is generally muted. Successive Scottish governments, anxious to stress an independent national identity, have made Gaelic a key feature of difference to England, and many would agree with Mackay that to care for a language that emigration and industrial economics so nearly wiped out is the mark of a civilised country.

And so Scotland is being Gaelicised, superficially and quite literally by tokens. The new Gaelic signs are what one notices most. For several years I thought they were merely local events, each individually explicable by their presence in or near the present boundaries of Gaeldom, or where tourists might see them ("Alba", for instance, on the boards at the border). But the plan is national because Gaelic has been designated a national language. Dual-language station nameboards, for example: eventually every Scottish station will have one, no matter how little the place was touched by Gaelic at any time in its history.

Recently, rattling through the Glasgow suburb of Cardonald, I noticed a new name on its austere platforms: Cair Dhòmhnaill. Which traveller would this help? None. Is it historically appropriate? No. In the 15th century, a Norman-sounding gentleman owned the lands of Cardownalde, which almost certainly derives from P-Celtic rather than Gaelic. Does any of this matter? Yes and no. According to Mackay, the sight of a Gaelic nameboard far from his home in Lewis "refreshes a part of my soul" and reminds him of Gaelic's fullest extent. More materially, it helps the tourist trade by rewarding visitors with the sense of the difference that all tourists seek; Mackay says the translated Gaelic menus in his local Indian restaurant in Inbhir Nis (Inverness) vanish for this very reason.

But I feel saddened by it. What I remember of Cardonald is the old Flamingo ballroom and council estates that were well thought of. To me, Cair Dhòmhnaill is a kind of instruction to focus on a far more distant history, like one slice of a many-banded core sample pulled from the earth, which has an arguable usefulness, and may very well be false.