Katrina Caldwell wants to talk about Songbird, the forthcoming Giant production, in the quiet space beside the library section of Easterhouse’s well-appointed Platform complex.

She and composer David Paul Jones are explaining why this new project is a musical tone poem, when a very small person – aged around three – hurtles past, vocalising a personal salute to the day. Even before Caldwell and Jones have got down to the nitty-gritty of Songbird, their case for stirring our imagination through sounds is falling on persuaded ears.

Then there’s the magical web of evocative sonorities and melodies that are in rehearsal elsewhere in Platform, the whole building is awash with the noises and cadences that influence our daily lives.

Caldwell explains that she’d been looking for five years for ways of channelling this energy and colour into a piece of music-theatre, one suitable for an inclusive audience of children with and without disabilities. “At Giant, we’d done these various other projects that had music in them. We’d seen first-hand the potential music had and how it could create atmospheres and encourage an emotional engagement, but we hadn’t really put the full focus on it.

“I felt a bit frustrated, we had to get to grips with this. So a couple of years ago I started spending time with composers, listening to a whole lot of different music.

“I didn’t know what I was looking for, I didn’t know what kind of music-theatre piece I wanted to make for an inclusive audience.”

Luckily, her path crossed with Jones, not just one of our most gifted composers but an intuitive troubadour of the heart and its journeys. Many a theatre company – the National Theatre of Scotland, Grid Iron, Suspect Culture and Catherine Wheels among them – has found its production sympathetically enhanced by his music and, on occasion, by his own performance. What drew him to Songbird?

“The music was going to be telling the story. Those little dots, the notes on the page, were the essence of the piece. In fact, it’s a chamber opera, though we’ve chosen to call it a tone poem, a lovely old concept you rarely hear referred to nowadays.”

It wasn’t just Jones’s music that moved and impressed Caldwell, it was his way with words. “My lyrics are non-literal sound poetry. I love writing for the voice, and I’ve always wanted to create a complete theatre piece out of a ‘language of otherness’. When Katrina was describing some of her ideas, Songbird just leapt out at me.”

Caldwell’s scenario sounds simple but has profound and cogently topical depths. An exotic songbird is endangered because “progress” is destroying its natural habitat. Then, rather like the King Kong saga, it is lured into captivity, put on stage to sing, but dies, crushed by human greed and thoughtlessness.

Back in rehearsals, Judith Williams’s sweet-voiced Songbird is in neat brown plumage. Come next week, she’ll slip into fine, brilliantly coloured feathers courtesy of designer Brian Hartley. It’s the moment when Rachel Hynes has just enticed the Songbird on board ship – the piano is their actual barque, with cellist Robin Mason as the figurehead – and Jones’s “language of otherness” is filling the space with a thrilling odyssey of hope.

“David’s non-literal phonetic language seemed to me a great leveller,” says Caldwell. “A new and unique language for everybody – and in terms of children with disabilities, there’s no advantage or disadvantage attached to the lyrics. The sounds, the music, the singing and the acting, that’s what matters. And being close to the performance.

“At workshops, we’ve had children fascinated by seeing a real piano and a cello, for the first time. This is also about bringing a kind of music to them that they might not have heard before. Letting them hear and feel something new and beautiful.”

Songbird premieres at Platform, Easterhouse, where it runs from October 19 – 23 before touring.