It might sound funny, but Ulster Scots is officially a language. The chair of the Ulster Scots Agency talks to Fionola Meredith.

Mark Thompson has a difficult job. He's chair of the Ulster Scots Agency, the cross-border body set up following the Belfast Agreement, to promote the Ulster Scots language and culture within the island of Ireland. Ridicule comes with the territory when you head up Tha Boord o Ulstèr-Scotch. After all, Ulster Scots, or Ullans, is a language (or dialect, depending on your viewpoint) with rich comic potential, brimming with colourful phrases.

For instance, the saying "as God grants" emerges as "whutiver's allooed", while the exclamation "Alas!" is translated as "waesucks!". So far, so funny - but the humour takes on a more serious edge when it's used to undermine the entire Ulster Scots movement. Some nationalists in the North have derided Ullans as "a DIY language for Orangemen", claiming that Ulster Protestants are simply intent on hoovering up government cash otherwise destined for the promotion of the Irish language by the agency's counterpart, Foras na Gaeilge.

Then there's the antics of Thompson's flamboyant predecessor. Lord Laird of Artigarvan attracted widespread public criticism when, at tax-payers' expense, he took a taxi rather than the train from Belfast to Dublin, so he would not have to appear in public in his kilt. Lord Laird defended the move on security grounds.

One year into the job, Thompson appears remarkably unruffled by all the flak. A graphic designer by trade, the genial 33-year-old has been involved with grassroots Ulster Scots groups for more than 10 years. He is also a member of the Low Country Boys, an old-time hillbilly/Ulster Scots gospel group.

"It's a shame that people still automatically assume that Ulster Scots is an invention, made up as counter-balance to Irish and all that," he says ruefully. "I'm not interested in the political dimension in the slightest - for me this is about culture, heritage, upbringing. When I was growing up, we had Catholic neighbours who would come and help my dad out on the farm, who were as good a speaker of Ulster Scots as my father was. The politicisation has put a lot of people off."

Thompson was born into an Ulster Scots-speaking family in the Co Down fishing village of Ballyhalbert, part of an area known as "the low country", where he still lives with his English-born wife and children. Fearful of appearing yokelish or provincial, the young Thompson hid his broad "mither tongue" when he went to secondary school. "All the kids from the low country realised you had to change the way you spoke when you arrived at the gates of the grammar school, so we quickly developed two modes of speech. There was a definite social stigma." It was not until many years later that Thompson discovered the rich Scottish language and literary traditions that echoed the familiar words of his early upbringing.

Although Ulster Scots is closely identified with unionism and loyalism, surely one of the greatest challenges for the agency is to reach out to the many people, both Protestant and Catholic, who have been seriously turned off by the perceived flakiness of the movement. There were plenty of sniggers in 2002, when the post of chief executive of the agency was advertised. Candidates were informed that they "maun hae wrocht for thrie yeir or mair as a high-heidyin in a tap offis jab" (must have a minimum of three years' appropriate experience as a senior executive). More recently, the reported claim that the phrase for disabled children in Ulster Scots was "wee dafties" had many people recoiling in horror.

"Well, that was seized upon, but I'm told it wasn't even a real translation," says Thompson. "And anyway, the agency's core function is promotion and awareness - that's what we're there for, not to establish linguistic standardisation. Thanks to the high profile of my predecessor, probably everyone on the planet knows of Ulster Scots. Having said that, what do they know about Ulster Scots? I see that as my role: starting to fill in the blanks and bring some credibility."

But what about all those dodgy-sounding neologisms such as "high-heidyin" (aka senior executive): don't they reinforce the notion that Ulster Scots is really a dialect masquerading as a language? Thompson rolls his eyes humorously at the inevitable question.

"The official response is that it's a language because the legislation says it's a language. Some people want to have the debate over dialect for genuine reasons, but others do it to belittle the identity of the entire Ulster Scots community."

Earlier this year Thompson was instrumental in arranging commemorations of the 400th anniversary of the Hamilton and Montgomery settlement, a pre-Plantation scheme in which 10,000 Scots were settled in counties Down and Antrim. Billed as the "Dawn of the Ulster Scots", it was clearly an attempt to answer the claim that Ulster Scots is an artificial invention. "It's one of the great untold stories," says Thompson. "And yes, it does help to put a foundation in. People are starting to see that there is some depth and resonance in all this."

With the advent of Thompson, the Ulster Scots Agency is starting to acquire vigour and credibility. "So far, I've tried to offer a reasonably normal presentation of what Ulster Scots means," he says. "We don't foam at the mouth, you know."