Living with Beckett and his words for 18 months, in performances from London to Greece to New York to London, forces one to go beyond language to the silence we all must face, writes Fiona Shaw

A WOMAN, "about 50, well-preserved", is how Samuel Beckett suggests Winnie, the heroine of his play Happy Days, should appear. So when the part was proposed to me 18 months ago, I was appalled, thinking at 48 that I was a woman "about 40". It is in these vanities, the gap between our self-preservatory illusions and reality that Beckett's genius captures actor and audience alike.

I struggled to meet Winnie, feeling that I was not allied to Beckett's sensibility. The writing reared up and resisted what normally happens when I make friends with a text. Usually I can find a line, a phrase or an image that reminds me of the poetry of my own life. I often find my childhood in plays and, no matter how far away the story or period, I hear my early self in the words, like a noise from a cave, but this was hard to learn - Beckett has taken phrases that sound like real speech, yet they disintegrate just as the images form. The effect on the hearer is genius: instead of frustrating the audience, he keeps them on tenterhooks hoping that the launch of the next phrase will make sense of what has gone before. The play's form and content are the same - pointless hope - so the audience rides the play in the very rhythm of its telling.

Every morning before rehearsals I met our stage manager, who drilled me inch by inch before the painstaking rehearsal period began. We played badminton in the coffee breaks so that my circulation would not prematurely seize up, and I spent Christmas Day in Cork drilling lines.

By the time we opened at Britain's National Theatre I was a thing of worry.

There began Beckett's first gracious revenge - to my surprise, the audience responded with so much humour, full of recognition of Winnie's plight, and she began to graft on to me.

The play has since travelled the world, a privileged way to develop the work and test its qualities against different cultures. We began in Epidaurus, Greece, by which time I had acquired a puppy who was taking over my life. He attended rehearsals and entertained us with his tilting head and earnest attempts to cope with me buried up to my waist in the mound. There was fierce debate in the Greek press as to whether a modern play should be performed on that ancient monument. At the time, I was more concerned with the difficulties of playing to a huge audience.

We anticipated 5,000 people, the population of a small town. But the ancients thought of everything. The acoustic of this remarkable amphitheatre is famous - an actor can stand on the stage and be heard whispering some hundred rows back, due, they think, to giant jars that sit under the orchestra.

My enthusiasm for the architecture was only tempered by the alignment between the burning images in Happy Daysand the fires raging through Greece that week. During the press conference a helicopter flew over carrying a giant sack of water to quell yet another forest fire, and I thought of Winnie's lines: "Is it not possible, with the sun beating down, and so much fiercer down, things to go on fire never known to do so in this way, I mean spontaneous like."

That night, the ancient theatre had the quality of an etching of the human brain, a tiered slice that fills the eye. I felt the slide rule of time did not apply. I was entirely in the past and in the present at the same time - all the people who had sat there, in togas two millennia ago, now in T-shirts and jeans - but I felt the frisson as I hit the lines: "Might I myself not melt in the end, or burn, I do not mean burst into flames, but little by little be charred to a black cinder, all this visible flesh."

The following morning, in the hotel, local tourists were weeping. The hills outside Athens were burning, and within an hour our second performance was cancelled, as were all performances in Greece. Official mourning was declared. Theatrical tragedy had given way to the real thing. We promised to return.

On to Paris, where the French vie for the ownership of Beckett, then Madrid in the giant old slaughterhouses lit with the neon blue the new Spain has made its own - and despite the surtitles, the Spanish laughed. I stood under the statue of Lorca and thought there is nothing we can teach these folk about the incremental catastrophe.

Then to Washington and on to New York after Christmas, where the play came into its own. I had wanted from the start to go there. Americans have always been attuned to rhythm, having absorbed so many languages, and I felt that the ease with which they had taken the dark humour of Medeamight again be there. Sure enough, they were so quick it allowed me to widen the gaping abyss in the play without having to underline it.

Then Amsterdam, where the first night was a sombre evening when Queen Beatrix came (a woman I had known only from stamp collecting!), but the following day the commoners seemed to enjoy it.

THIS SUMMER, we returned to Epidaurus. We drove past the healing scalps of mountains, past verdant forest saved by man-made scars cut into the land. I thought, if only we could do the same and limit damage in ourselves: the burned mind of Winnie making less and less sense ("This . . . Charlie . . . kisses . . .this . . . all that"). Where before I had embraced the play's universal significance, this year I was more personally chastened by it. Near the end of the play, Winnie has a revelation: "I used to say Winnie you are changeless because there is never any difference between one fraction of a second and the next."

For many years I might have said the same thing: most of the dramas in my life have been of my own making. But something of the play has caught up with me. I have suffered losses this year, among them a young Greek member of our team. Last June I went to the funeral of our director Deborah Warner's father, and in the same week my own father suffered a stroke, and after New York my little dog was killed. Winnie refers to these "little . . . sunderings, little falls . . . apart", and now I am chilled by the lines: "To have been always what I am - and so changed from what I was."

I learned this year that the theatre at Epidaurus was a later addition to a site that had been a healing place. The sick climbed the mountain, slept the night in tents, and in the morning could diagnose their own illness, the god Asclepius having visited them in the night to inspire them. The climb was part of the healing process, the acknowledgment that something was wrong. Perhaps this is what drives us to a theatre, to hear the sounds of our own mortality - and yet laugh.

We performed to 6,000 people. Beckett takes us beyond language to silence, the silence we all will and must face. We may find it holds desolation, but one feels that, against all odds, it holds promise. A week later I turned 50. Winnie and I have met.

• Fiona Shaw appears at the Abbey in the British National Theatre production of Happy Days, directed by Deborah Warner,from tomorrow until Oct 25 as part of the Ulster Bank Dublin Theatre Festival. Booking: 01-8787222