The last time the world of music heard from Polly Harvey was more than seven years ago, in the spring of 2016. Brexit had yet to happen, Barack Obama was still president, and the 53-year-old was on a world tour, albeit the kind of tour the late PJ O’Rourke conducted to research his 1988 opus Holidays in Hell, rather than the kind that involves roadies, riders and soundchecks. The Hope Six Demolition Project, Harvey’s ninth studio album, offered a travelogue of ravaged locations around the globe – Afghanistan, Kosovo, the roughest neighbourhoods of Washington DC – that Harvey had visited in the company of photographer and film-maker Seamus Murphy. It was clearly a process that she ultimately found exhausting: by the end of the accompanying run of live shows, she was apparently considering retiring from music entirely.

She didn’t, but after seven years of dabbling in film and television scores and doing whatever it is that Polly Harvey does when she’s not being PJ Harvey (which frankly could be anything from practising diabolism to getting the prosecco in and inviting the girls over for Love Island – few contemporary artists have so successfully drawn a complete veil over their personal lives), she has returned in a very different place. The one similarity between I Inside the Old Year Dying and its predecessor is that it arrives preceded by a book of poetry, Orlam, an alternately disturbing, dream-like and mysterious novel in verse: I Inside the Old Year Dying essentially adapts 12 of its poems for lyrics. They are set very close to home, in Dorset – where Harvey was born and still lives – and written in thick, occasionally archaic local dialect. Orlam came with a glossary, which is useful when listening to the album, although you don’t need it to understand why Harvey might be enthralled by the language she uses, above and beyond simply geographically rooting the songs. Chawly-wist, clodgy, giltcup, reddick, un-gurrel, puxy: these are words that sound great – rich and satisfying in the mouth – even if you don’t know what they mean.

Besides, the glossary won’t help much with the enigmatic plot, involving a girl on the cusp of adolescence, escape into nature, ghostly “chalky children of evermore” and a spectral, Christ-like figure called Wyman-Elvis, whose speech mingles the lyrics of Love Me Tender with Jesus’s teachings from the gospel of John (anyone interested in drawing parallels between Harvey’s work and that of her sometime collaborator Nick Cave might note a link to Cave’s 1985 epic Tupelo, which conflated Presley’s birth with the nativity). Its obscure nature is occasionally slightly frustrating – it would be nice to know what’s going on, because what’s going on sounds fascinating. But rather than puzzling it out – or indeed, rooting through it for inferences of autobiography – it’s probably better to just immerse yourself in the atmosphere the album creates.

I Inside the Old Year Dying is at the opposite end of Harvey’s musical spectrum to the muscular garage rock and massed backing vocals of The Hope Six Demolition Project. The drums and Harvey’s keening vocals are very in your face: the former recorded without reverb, so they appear to be playing directly in front of you; the latter uncorrected, with every sibilant “s” and microphone-popping “p” sound – and indeed the odd bum note – left in, giving a sense of first-take immediacy. Everything else floats somewhere in the middle-distance, a gauzy mass of fingerpicked acoustic guitar, flickers and gusts of feedback, trombone and synthesiser in which individual instruments are often hard to pick out.

The effect is oddly disquieting, the weird mix lending a disturbing, fever-dream edge to the prettiest melodies, as on A Child’s Question, August. Even Seem an I, which moves from unaccompanied folk-ish singing to the kind of tough guitar riff and strident backing vocals Harvey would have turned into something straightforwardly forceful on The Hope Six Demolition Project, sounds weirdly smeared, smothered in electronics that spin out of time with the rest of the track. The album is frequently overlaid with field recordings of children playing, powerlines humming, rivers rushing and wind rattling fences, a cocktail of sounds that evokes the mood of an ominous old public information film.

There are moments where stark images punch through – “I ascend three steps to hell, the school bus heaves up the hill,” she sings on Autumn Term, as potent a description of first-day-at-secondary dread as you could wish for – but, for the most part, I Inside the Old Year Dying is pretty inscrutable. It requires the listener to submit to its immersive world – a world that, frankly, only PJ Harvey would have dreamed of conjuring up in the first place – but that’s not a problem. Like the Dorset woods they describe, I Inside the Old Year Dying is eerily forbidding, but intoxicating, and easy to lose yourself in.

• I Inside the Old Year Dying is released on 7 July

This week Alexis listened to

Say She She – C’est Si Bon
Not a cover of the old 70s classic by Dr Buzzard’s Original Savannah Band, but the first track from Say She She’s second album is nevertheless a joy: funky, poppy, entirely delightful left-field disco.