In 1982 the first album on the now defunct Loco label appeared and I bought a signed copy in my home town of Cwmbran. The appeal to me of this 17 track record was manifold. Firstly, it was in Welsh, a language I was trying to get my head round at the time (and am still trying). Secondly, the informative and attractive booklet with it claimed that there was a Gwentian dialect of Welsh, used on the album. Some of the band were actually from Cwmbran. (One of them had given my sister guitar lessons and his sister was the headmistress in the school where I did my teacher training). Thirdly, it is a folk album, more Irish than Welsh in many respects, so right up my street musically. You can no longer get hold of the album although one or two tracks can be found on i-tunes.and an album in the same mode Gwentian was released a few years ago. I must check it out some time. I have only a poor recording of the original vinyl on my computer. The album includes versions of Bachgen Bach o dincer and Ymh Mhontypridd as well as a number of tribans.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.