In 2011, DIY promoters Cry Parrot and Tracer Trails joined up to launch Music Is The Music Language, a Glasgow festival designed to celebrate Scotland’s underground music in all its fascinating forms – from folk to noise, electro to hip hop.

Now going by the Music Language moniker, and chiefly under the jurisdiction of Cry Parrot, the festival continues to explore our subterranean realms, to thrilling effect. This is testified by the diversity and quality of the artists performing this year (it takes place in Glasgow on September 6–8), many of whom are featured on this excellent accompanying 24-track album – including languid-pop seducers eagleowl, techno-punk deviants Golden Teacher, dream-rock heartbreakers The Yawns and Alex Neilson’s a cappella madrigal troupe, The Crying Lion.

It traverses spellbinding warm-machine side-projects (Conquering Animal Sound’s Anneke Kampman, alias ANAK-ANAK), vital solo endeavours (Tattie Toes’ Howie Reeve), and all manner of treats and works-in-progress – from live offerings (Death Shanties’ ‘Obsidian Ovarian’) and scratchy post-punk demos (Seconds’ ‘When He Calls)’, to riveting avant-garde extracts, thanks to anti-supergroup Asparagus Piss Raindrop’s ‘Dream Within A Dream (edit)’ and the sublime ‘Bradford Threadfest (excerpt)’ from Jer Reid, Stevie Jones, Aby Vulliamy and George Murray.

Opening with the mesmeric, tropical kitchen-sink techno of Dick 50’s ‘Eq’, and boasting countless sonic delights like Hausfrau’s ice-cool lounge-electro (‘Dancehall Days’), Ela Orleans’ extraordinary ‘Beat Goes On’ and Magic Eye’s submerged pop lullaby ‘St Rita (Space Echo version)’ – not to mention Vars of Litchi’s jazz-punk wig-out (and brilliantly titled) ‘Yr Maw’ – Music Language 2013 is roundly surprising, entertaining and enlightening.

All proceeds from the album go to Music Language production costs (it’s a not-for-profit enterprise), and the download is well worth whatever hard-earned coin you can afford. It may be available under the banner of pay-what-you-will (which could be nothing), but don’t be misled: as an introduction to some of the finest under-radar, off-kilter and outsider music Scotland has to offer, this compilation is priceless.