Using NLP to build a Black Metal Vocabulary

Black metal is typically linked, since its inception, to Satanic or anti-Christian themes. With the proliferation of bands in the 90s (after the Norwegian boom) and subsequent emergence of sub-genres, other topics such as paganism, metaphysics, depression and even nationalism came to the fore.

In order to discover the terminology used to explore these lyrical themes, I’ve devised a couple of term extraction experiments using the black metal data set. The goal here is to build a black metal vocabulary by discovering salient words and expressions, that is terms that when used in BM lyrics carry more information than when used in a “normal” setting. For instance, the terms “Nazarene” or “Wotan” have a much higher weight in the black metal domain than  in the general purpose corpus used for comparison. Once again note that this does not necessarily mean that these two words occur very frequently in BM lyrics (I’d bet that “Satan” or “death” have a higher number of occurrences), but it indicates that, when they do, they carry more information within the BM context.

This task was carried through JATE‘s implementations of the GlossEx and C-value algorithms. The part-of-speech of each term (that is, the “type” of term) was discovered with the StanfordNLP toolkit. The top 50 of each type (with the exception of adverbs) are listed in the table below. For the sake of visualization, I make a distinction between named entities/locations and the other nouns, being that the former are depicted in the word maps at the end of this post.

I’ve also included, in the last column of the table, the top term combinations. It’s noteworthy how much of these combinations are either negations of something (“no hope”, “no god”, “no life” and so on), or concerned with time (“eternal darkness”, “ancient times”). Such preoccupation with large extensions of “time” is also evident in the top adverbs (“eternally”, “forever”, “evermore”),  adjectives (“endless”, “eternal”) and even nouns (“aeon” or “eon”).

ADJECTIVES ADVERBS VERBS NOUNS TERM COMBINATIONS
Endless Nevermore Desecrate Forefather Life and death
Unhallowed Eternally Smolder Armor Human race
Luciferian Tomorrow Travel Aeon No light
Infernal Infernally Fuel Splendor No hope
Necromantic Forever Spiral Pentagram Eternal night
Paralyzed Anymore Dethrone Perdition No god
Pestilent Mighty Throne Specter Full moon
Unholy Skyward Envenom Misanthrope No life
Illusive Evermore Lay Cross Black metal
Untrodden Earthward Resound Magick Cold wind
Astral Someday Mesmerize Nihil No place
Misanthropic Astray Abominate Ragnarok No escape
Unmerciful Onward Paralyze Blasphemer No return
Cruelest Verily Blaspheme Profanation Eternal life
Blackest Deathly Impale Misanthropy No fear
Eternal Forth Cremate Malediction Flesh and blood
Wintry Unceasingly Bleed Revenant No matter
Bestial Weightlessly Procreate Damnation Fallen angel
Reborn Anew Enslave Conjuration Eternal darkness
Putrid Demonically Awake Undead No man
Darkest Behold Nothingness Dark night
Unblessed Intoxicate Armageddon Lost soul
Colorless Devour Lacerate No end
Diabolic Bury Wormhole Ancient time
Demonic Demonize Eon No remorse
Wrathful Forsake Devourer No reason
Nebular Enshroud Impaler No longer
Vampiric Writhe Sulfur Black cloud
Unchained Destroy Betrayer Dark forest
Armored Entomb Deceiver Human flesh
Immortal Raze Bloodlust Endless night
Hellish Flagellate Reaper Ancient god
Hellbound Unleash Horde Mother earth
Unnamable Convoke Blasphemy Black wing
Prideful Crucify Eternity Night sky
Colorful Fornicate Defiler Dark side
Unbaptized Torment Immolation Eternal sleep
Unforgotten Venerate Soul Black hole
Satanic Beckon Abomination Black heart
Morbid Defile Flame Flesh and bone
Sempiternal Distill Hail No chance
Mortal Immolate Malignancy Dark cloud
Honorable Welter Wrath Final battle
Glooming Run Pestilence Eternal fire
Willful Sanctify Gallow No peace
Lustful Eviscerate Disbeliever No future
Everlasting Unchain Witchery Black soul
Impure Ravage Satanist Final breath
Promethean Mutilate Lust Black night

Most salient entities: many are drawn from the Sumerian and Nordic mythologies. I’ve also included in this bunch groups of animals (“Beasts”, “Locusts”).

Most salient locations. I’ve also included in this bunch non-descript places (“Northland”). Notice how most are concerned with the afterlife (surprisingly, “hell” is not one of them).

It occurred to me that these results could be the starting point of an automatic lyric generator (like the now defunct Scandinavian Black Metal Lyric Generator). Could be a fun project, if time allows (probably not).

Resources:

IBM GlossEx

Jason Davies’ D3 Word Cloud

JATE – Java Automatic Text Extraction

StanfordNLP Core

Middle-Earth Entity Recognition in Black Metal Lyrics

The influence of JRR Tolkien in black metal is pervasive, almost since its beginning. One of BM’s most (in)famous outfits, Burzum, took its name from a word invented by the Middle-Earth creator that signifies “darkness” in the Black Speech of Mordor. Other Norwegian acts such as Gorgoroth or Isengard adopted their names from notable Middle-Earth locations. Perhaps the best example is the Austrian duo Summoning, who have incorporated in their releases inumerous lyrical references (well, not inumerous, about 70 actually) to Tolkien’s works.

The references to Middle-Earth mythology abound in both lyrics and band monikers. Using a list of notable characters’ names and geographic locations as the basis for a named entity recognition task, I set out to find which are the most cited in the black metal data set.

With this list and a small Java NER script implemented for this task, I found 149 bands which have chosen a Middle-Earth location or entity for their name. Angmar is the most popular (6), closely followed by Mordor (5) and Sauron (5). With 4 occurrences each, there’s also Orthanc, Moria, Nargothrond, Carcharoth, Gorthaur and Morgoth.

As for actual lyrical references to these entities, I found a grand total of 736 of them. The ones that have at least two occurrences are depicted in the bubble chart below. It’s not surprising at all to find that the most common references (Mordor, Morgoth, Sauron, Moria, Saruman and Carcharoth) belong to malevolent characters, or dark and dangerous places, of the Tolkienesque lore. The “Black Gate” is also mentioned a lot, but it could have a meaning outside of the Middle-Earth mythology.

Credits

Bubble Chart built from Mike Bostock’s example