As a long-silenced student of that most democratic of instruments, the tin whistle, I have waited 20 years to meet Mary Bergin, a woman I never really had an image of - except for the cover of that first solo album, Feadoga Stain, Rick Ward's beautiful painting of a male stone-chat, perched on a sprig of gorse - an apt representation of her infinitely melodic, perfectly ornamented, vigorous playing.

Remarkably, she made a science, a high-art form, and indeed a life, out of an often denigrated and fallible little instrument. Feadoga Stain came from nowhere in 1979 - its unparalleled discipline and metronomic groove making it one of the uncontested bedrock albums of Irish traditional music. Yet after an explosion of busy commercial recording in the interim, people don't talk in the same breath of Feadoga Stain 2 (1992). But it's a similar Everest for musicians, with tunes that grab the heart, like Eileen Curran's reel, or the bare love-lament, Seolfaimid Araon na Geanna Romhainn (We'll walk the geese home together again).

Grubby off the bus, I traipsed out of Spiddal into its road-ribbon suburb, and up the rough gravel driveway to the glinting new suburban house with its wildflower bog of a garden. And there she was: the big, pretty, open, strong-boned face, framed by an aureole of huge silvery ringlets of hair; a scatty, utterly unassuming and vigorously thin woman full of laughter as she wandered around the house, hunting out whistles and putting on the kettle.

We sat out at the back of the house, looking out of the rambly garden, sloping into scrubby bog and dry-stone walls towards Galway Bay, the air filled with suitably ardent birdsong. Born in 1949, Mary came from the Pale, in Shankill, which was countryside then. Her mother played classical and traditional fiddle, and her late father played the melodeon. Musicians regularly called to the house, like Paddy Hill, Mrs Crotty and Mrs Harrington. "They were old even at that stage, I remember the purple dye in their hair. Every year, we would go into the Oireachtas, and I heard Willy Clancy play the whistle - he had long hair at that stage - but I was very influenced by him."

Gradually, Mary and her sisters began to play in sessions in Blackrock, where she met the blind whistler Terry Horan and fiddlers Joe Liddy, Kathleen Nesbitt and John Dwyre, and indeed the younger Micheal O hAlmhain, who took her off to her first fleadhs, and they discovered the sessions in Church Street and the Pipers' Club. "We ate and slept and drank music."

Her exemplary playing led to Comhaltas tours of the UK (with people like Liam Og O Flynn and Matt Molloy) and the US (with Seamus Begley, Joe Burke and James Kelly), and she briefly worked in Comhaltas administration, where her ambitions in library and field work were often stultified. "My concern was the regional styles, which were totally neglected at a time when the older musicians were dying off, and the new radio and television programmes meant that the styles were becoming amalgamated." But they fed into her own playing, as she drove around the country in her mother's blue mini. "I used to focus in on the older musicians, old fiddle and flute players like Packie Duignan."

Meanwhile, playing with other outfits like Green Linnet (successor to the old Castle Ceili band) and Ceoltoiri Laighean. She married an Australian instrumentmaker, Bruce Du Ve, and they set up a business, which, after much dithering between the IDA and Shannon Development, went bust. Around that time, their marriage broke up. "It wasn't an easy time, and the babies were only small, it was tough in the beginning for me.

"I faded off the scene in a way because I wasn't in a position to travel, and I'd lost heart in playing because my life was on a bit of a downer, but this friend over the road, Nancy Neachtan, used to take the kids, that's how I started teaching - although there were also good gigs at festivals in Sweden, Denmark and Finand." When I ask if she ever had another relationship, she says quietly, "No, I never really met anyone."

She still teaches locally in schools (in groups, graded by standard rather than age) as well as by correspondence to America, England and Australia, and she has recorded a full private course over four CDs. "I used to fly out to the Aran Islands on the small little plane and teach the class for the day and come back again."

Another thriving sideline is her collaboration with fiddler Dearbhaill Standun and harpist Kathleen Loughnane, called Dordan (the Irish for "a buzzing/humming as of bees"). Blending baroque with Irish music and ornament, they have increasingly moved from Purcell and Handel pieces to new compositions of their own. They have just finished recording an album with that great wandering musician, Steve Cooney. She showed me her own instruments in a little wooden box like a backgammon case: an endearing and un-heroic looking jumble of English-made Generation whistles, or whistles made by John Sindt, Pat O'Riordan and Michael Copeland, and one wooden one with three metal keys, found on a dusty shelf in the old nearby gate lodge of Lord Killanin, where she lived for a decade.

The whistles looked injured, with tape pasted over parts of the holes "to bring them into tune with themselves". She laughed. "That's my career in a box, look at the state of it. I'm as bad as Tommy Peoples going round to the Church Street sessions with a fiddle in a brown paper bag at one stage."

With regard to traditional music education, she hasn't yet examined the new schools' syllabus between Comhaltas and the Royal Irish Academy of Music. "I'm not an authority, but my experience is that there are different rules for different schools. And they don't teach enough theory or history of musicians Turlough O Carolan and Cornelius Lyons, or old instruments like harps and pipes. The practical should go hand in hand with the theory, rather than being allowed as a token thing.

"Obviously, there'll be teething problems with a new subject, but the classical teachers are being used to examine in traditional music, and they're not qualified. They need a new whole panel of people, if the effort isn't to be half-hearted.

"Also one fear I would always have, even in my class situation, is that the emphasis is on technicality, whereas for me, the whole thing is the feeling and heart and soul, that's what the older musicians had - something special, an internal rhythm, that nya! or sway, you find yourself moving your shoulders. "I don't think you can teach that, it comes with feeling, and mixing with people that have it, and it's important to impart that right from the cradle - even from an enjoyment and social point of view, the sharing of the playing."

She has also become disillusioned by competitions. "I've adjudicated at Fleadhs, but I don't like it, because you only end up with one friend, the winner. And again, if an adjudicator is biased towards one particular regional style, that'll win. And if that adjudicator is there for two or three years in a row, the children - they've said it to me - will work on that style.

"Initially the competition idea raised the standard for the music when it was at a very low ebb, back in the 1950s, but nowadays I think there's no need for it because the standard is so high. I would prefer to see exhibitions rather than competitions."

Later, in her sister Antoinette's hideaway outside Roundwood in Wicklow, I caught a glimpse of the urgent generosity of Mary's teaching. Has she ever composed tunes before Dordan? "I had written some, but I forgot them or lost the tape, I'm not one to write music down. And I never would have played them out in a session, I would have felt self-conscious. I never even had that much meas on them myself."

So will there be a Feadoga Stain 3? She gives a sharp intake of breath. "I don't know, I have promised Martin O'Hare in Copenhagen to do one, but I don't know what's holding me back. There's so many records coming out now, I begin to think I have nothing new to offer, just a repetition of what I've done already . . ."

Oh go on, Mary, for the good of the music.

Mary Bergin is currently on a two-week Music Network/ESB tour with her brother-in-law, piper Joe McKenna, Mick Conneely on fiddle and Noel Shine on vocals/guitar. Information from: 01-6719429.