A re-imagining of the Joni Mitchell album Hejira in the Scots language and in a Scottish setting will be a festival centrepiece later.

Described as one of the highlights of this year's Celtic Connections, Pilgrimer, as it has been re-titled, will be premiered.

It is 40 years since Canadian-born singer-songwriter Mitchell released her album.

It was born out of what were often solo journeys across the United States.

She sang about the sights and sounds, the people she met, the experiences.

As the title of one track puts it - The Refuge of the Roads.

Three years later, a young Scot who had been hitchhiking around North America first came across some of that music. James Robertson later became a poet, novelist and champion of the Scots language.

"These songs really began to speak to me as songs about experiences that I myself had had", he explains.

"I think that's why this whole album of songs got into my system and into my bones and has been there ever since, for the best part of 40 years."

About 20 years ago he took the opening track of the album - Coyote - and began playing about with it.

The result was written in Scots, but came out as a poem about a fox, also known as a tod. Some time later, he began looking at some of the other songs on Hejira to see if he might do something similar.

"They're not translations, the word we're using is re-imaginings," says Mr Robertson.

"The words have shifted into Scots but as that has happened, the words have also relocated both geographically and in terms of what they're about, but anyone who knows that album will recognise the tunes."

Where Joni Mitchell sings about the music scene in Memphis, he moves his song to Dundee, referencing singers like Michael Marra.

It was only after a conversation with the Celtic Connections director Donald Shaw that the idea of putting on a concert moved closer to a reality.

There have been challenges to overcome along the way.

"Essentially the words were written as poems and the challenge has been how to make those poems become songs," says songwriter Karine Polwart. Along with her brother, Steven Polwart, she has provided musical direction for the project.

In the past few months she has listened to Hejira 50 or 60 times.

"Joni Mitchell writes in English and she sings in a North American accent," continues Ms Polwart.

"Scots sounds very different, the vowel sounds are different, the consonants are more percussive, so a lot of things that, on the page might look like they're a direct match in terms of syllable and meter for what is written in English. It can't be sung in the same way.

"That has involved a bit of back and forwards, sometimes changing a word or sound so that it works better as a song.

"It's very much his (James Robertson's) vision and his lyrics but between myself and my brother Steven as musical directors we've been thinking about these lyrics as songs."

Hejira is about journeys and the last year or so has seen unprecedented numbers of people on the move across the world.

"On the road in the same way that Joni Mitchell was but for very different reasons today," says James Robertson. That was in his mind when he was thinking of a title - the word he settled on was pilgrimer.

He added: "It's an old Scots word. It really means pilgrim but it's got this extra syllable and I think it's a very beautiful word.

"There's a little catchphrase that I picked up from a 16th century source which goes like this:

'In this life, we are but travellers, pilgrimers and strangers looking for habitation.'

"That to me captures what a lot of people are on the move for today, they're looking for a place of safety and a place they can call home.

"That seemed to fit in with the ethos of what this whole project is about."