Liam Ó Muirthile's latest collection might be lighter in tone, but the old darkness is still there, he tells Catherine Foley

The poet Liam Ó Muirthile describes a clearing he came across one evening some time ago among the trees in the Wicklow mountains. It was the rounded space, which is left by a rutting stag. He uses this dark space as a metaphor for the darkness that a person can sometimes get drawn into.

The dark force of the stag is compelling, he says, but "the great freedom is not to give it the power over you. You can acknowledge it being there and at the same time walk away from it.

"It was like the old darkness revisiting me," he recalls. An Damh (Stag) is one of the poems included in his new collection, Sanas. "We do carry a lot of darkness from our backgrounds but it has to shift," he explains.

This is Ó Muirthile's sixth collection of poetry. He has won many awards since his first collection, Tine Chnámh, which won the Ó Riordáin Prize at the Oireachtas competition, was published in 1984. He accepts that there is a sense of brightness and lightness in this new collection, which deals with themes including love, friendship, childhood, family, loss and beauty. Maybe that lightness, he reasons, "only comes with maturity . . . We start being playful as children and then we go through long periods of self-discovery. I think if you can reach the point of playfulness in your own life, I think it's a great joy because that's where the real truth is," adding quickly, that "you can be serious and playful at the same time.

"I think I had to go back in my own life to the stage where I learned Irish and the first poem in the collection acknowledges that . . . The language itself had become a burden to me. I had to go back to the root of that and find out what that was saying to me."

In this collection, he's found "a new seam of language within myself", explaining that "poetry in the end is about language, and the mining of language and seeing what it is saying to you. I felt that I'd gone deep enough" into the Irish literary tradition. "I just couldn't continue in that mine shaft. I had to change."

He wrote furiously last year. "I got a great run last autumn, the poems were falling out of the sky. I think that one of the factors for that is the tectonic movement in the unconscious."

Does writing in a minority language make a difference to a poet? "In one sense it does, in the sense that the reverberations coming from the work are weak. And the after-shock isn't there. But if you choose a path for yourself, then you have a responsibility to that choice. Making a commitment to anything is what's important . . . The original call is still there. It's just that you can lose the signal on the dial, it goes away faintly."

Then, he sighs and admits briefly, "you feel at times that we are just living under a rock, like a crab and there's nobody there, but I'm not sure if that's a very important thing at all".

Still, no English translations accompany the poems in this collection. "It's not the translation outwards that's interesting for me but the translation downwards," he says. It's "what sort of truths are underwater, fo-thuinn, in the unconscious, what truths are floating around there in that almost embryonic fluid, in a sense. You are almost back at a prenatal stage of time, the unconscious, I believe, and there are truths there. They'll take their time . . . I don't know what releases them but I do believe that it's paying constant attention to that interior murmuring, which is not only part of yourself but it's also part of the universe. It's always going on, the hum is always there."

IN THE OPENING POEM, Á É Í Ó Ú, he writes about the violent Christian Brother who taught him Irish. "He was a great man in his own right," recalls Ó Muirthile, but "I had to deal with the residual terror that I felt in that class, I did feel it. But at the same time I think it's very important not to condemn outright what we have gone through."

The book is accompanied by a CD with Ó Muirthile reading his work, including a number of soundscapes created by the singer Iarla Ó Lionáird. Ó Muirthile says the collaboration led to his pace becoming "much slower", and that it allowed him "to rest with the words, to take it at a different pace altogether".

Ó Muirthile is the eldest of nine children, and many of the poems recall growing up in Cork City. "The complexity of it for me was the fact that I learned Irish very seriously at the age of 11," he says. "I acquired the language. It was in the scholarship class when I was 10 and 11. We used to learn pages of dictionaries. We'd learn all the words. The paradox in my own case is that I grew up in a house where there weren't a lot of books. I read my first books in the Irish language and my first literary books were in the Irish language." He smiles as he remembers reading about Jeronimo in An Tíogar Daonna (The Human Tiger).

Then he pauses, at the mention of his poem Seanathair, which is about his paternal grandfather. "I have this picture of him," he agrees, "but I'm not sure if that's my grandfather or is it an archetype. I think it probably is an archetype . . . I'm only one of the elements of the body of my ancestors."

• Sanas is published by Cois Life, €15