I was very interested in this anyway, as a fan of both Sibelius and Tolkien. Sibelius's Kullervo Symphony is one of my favourite pieces by him, featuring deep orchestral and choral action as he tells the tragic story of the antihero and his sister. Tolkien might have been aware of its existence but could not have heard it when he wrote his own "Kullervo" in 1912-14; its last performance in Sibelius's lifetime was in 1893, shortly after Tolkien's first birthday, and Sibelius refused to allow it to be published until shortly before his death in 1957. So it's a case of two artists who I greatly admire taking the same subject matter completely independently within about 20 years of each other.
To describe Tolkien's work as a translation is to rather miss the point. This is a different case from his Beowulf which I wrote about a few months back. To illustrate, here is the passage describing the death of Kullervo's sister, in the original Finnish and two nineteenth century English verse translations, with Tolkien's prose version underneath:
|Sai toki sanoneheksi,
heti repsahti re'estä,
siitä juoksihe jokehen,
kosken kuohu'un kovahan,
Siihen surmansa sukesi,
löyti turvan Tuonelassa,
armon aaltojen seassa.
|Scarcely had the maiden spoken,
When she bounded from the snow-sledge,
Rushed upon the rolling river,
To the cataract's commotion,
To the fiery stream and whirlpool.
Thus Kullervo's lovely sister
Hastened to her own destruction,
To her death by fire and water,
Found her peace in Tuonela,
In the sacred stream of Mana.
|Soon as she had finished speaking,
And her speech had scarce completed,
Quickly from the sledge she darted,
And she rushed into the river,
In the furious foaming cataract,
And amid the raging whirlpool,
There she found the death she sought for,
There at length did death o'ertake her,
Found in Tuonela a refuge,
In the waves she found compassion.
|Tolkien: And before he could leap up and grasp her she sped across the glade (for they abode in a wild dwelling nigh to the glade spoken to him by the Blue Forest Woman) like a shivering ray of light in the dawn light scarce seeming to touch the green dewy grass till she came to the triple fall and cast her over it down its silver column to the ugly depths even as Kullervo came up with her and her last wail he heard and stood heavy bent on the brink as a lump of rock till the sun rose and thereat the grass grew green, birds sang and the flowers opened and midday passed and all things seemed happy: and Kullervo cursed them, for he loved her.|
Now, first of all, no English translation is ever going to capture the Finnish metre and alliteration (heavily copied by Henry Wadsworth Longfellow for Hiawatha); even if you don't know a word of the language, you can look at the extract above and see the repeated initial s, k, r, j, k, p, s, k, t, a in each line. The Finnish relies a lot also on repeated vocabulary, which looks very weird in most other languages (so most transltors try to find ways around it).
Tolkien's approach was not to even try, but to change the game. His Kullervo and his sister have had an ongoing relationship (sponsored by the Blue Forest Woman, who is an invention of Tolkien's not found in the Kalevala) rather than the brief encounter in the original (which features also two other women who successfully spurn Kullervo's advances). His description of the scene is far more detailed and naturalistic than the stark skeletal Finnish original, told in a stream of expression reminiscent of Woolf or Joyce (though he could hardly have read either in 1912). Also it has to be said that Tolkien's description of the scene centres more on Kullervo's perceptions than his sister's emotions.
But the biggest change of all is the context. In the Kalevala, this scene happens as soon as both Kullervo and his sister work ou their relationship. In Tolkien's version, she realises the truth but goes to her watery grave without telling her brother, who was to have found out from their mother in the bit Tolkien didn't get around to writing. It's the sharpest of many innovations in Tolkien's version, all of which basically reinforce the narrative (which is a tad confused in the orignal), and several of which can be directly tied to Tolkien's own biography and personal experience. The core incest story of Kullervo is of course also a core part of The Children of Húrin, the most successful part of The Silmarillion, though Kullervo and Túrin are very different characters and the bits about Kullervo's faithful dog were used by Tolkien instead for Beren.
Tolkien's "Kullervo" takes up less than a quarter of the newly published volume. The rest includes two versions of a lecture by Tolkien about the Kalevala, and a piece by Verlyn Flieger looking at the importance of the "Kullervo" piece in Tolkien's career. The lecture is typically lucid, and attempts to share his enthusiasm for an obscure language's national masterwork to a receptive but uninformed audience, with some rather profound reflections.
As the world grows older there is loss and gain –let us not with modern insolence and blindness imagine it all gain (lest this happen such songs as the ‘Land of Heroes’ [Kalevala] are left for our disillusionment); but neither must we with neo-pagan obscurity of thought imagine it all loss.
Fair play to the man, who despite his tremendous expertise in Germanic languages retained a genuinely keen interest in the lore of the Celts and Finns.
As Flieger suggests, "Kullervo" is a very important moment in Tolkien's own writing - his first attempt to take the ancient tales and craft something new out of them. The future writing of The Silmarillion wasn't really in Tolkien's mind when he wrote "Kullervo"; but "Kullervo" is very important as a pointer to The Silmarillion and to everything else. The fact that he didn't finish it is in itself significant - perhaps he realised that his future was never going to be in adapting other work for a new audience, but in taking its ideas and making them his own.
Anyway, as I said, I don't think that "The Story of Kullervo" itself is a convincing Hugo nominee, however cool it might be to nominate a century-old piece by the greatest writer of fantasy; but I think the book as a whole is a very interesting contribution to Tolkieniana and thus to understanding the overall growth of the genre, and I expect that I'll be nominating it for both the Best Related Work Hugo and the BSFA Award for Best Non-Fiction next year.