Those not familiar with Petty dwarves.. these were dwarves very much differed from normal Dwarves in various ways: they were smaller, far more unsociable, and they freely gave away their names; other Dwarves kept their Khuzdûl names and language a secret. This may have been one of the reasons the Petty-dwarves were exiled, but more on that later.

They were the first to arrive in Ered Luin in the First Age, and established strongholds in Beleriand before the building of Nogrod and Belegost in the Blue Mountains, and before the Elves arrived.

Petty dwarves had a different dialect, some might even go so far as to claim they had a different language. Though petty dwarves have long gone extinct by the Third age. The only remnant of their different dialect is the dialect used by the dwarves currently living in the Blue Mountains. Although not as strong a variant, it has been noted that the Ered Luin dwarves have a different dialect then dwarves from other regions, who speak a standard unchanged Khuzdul. It is unclear however what the accent changes are.

It is said that the writing “Nulukkizdîn” was an older version Tolkien devised, in later version it was replaced by its current form.

From its first conception, the name Nargothrond means “Underground fortress on the river Narog”. Its Petty-dwarvish name was Nulukkhizdîn (erronously spelled Nulukkizdîn in some published works).

However, in his later life, Tolkien devised the Dwarvish name Nar(u)kathan instead, to which the Elves suffixed -rond, “vaulted dome”.

Looking at the Petty dwarf name in neo-khuzdul first.
It consist of three seperate words, Nuluk – khiz – dîn

Nuluk : could be an older (or petty dwarvish way) of writing Nûlukh (which means moon).

Khiz : is derived from Khuzd, meaning “dwarf”

dîn: is a shortened from of zdîn, meaning “land”.

So litteraly this would mean: “the land of the Moon-Dwarves”.

Let’s look at the later dwarvish name of Narukathan.
Again consisting of 3 words: “Nar – u – kathan”

* Nar: a referrence to the river (or the name of the river: “Narog”)

* u: indicates “of”

* kathan: could be derived from “khathuzad”, meaning “elves”

Full meaning would be: “Elves of the River (Narog)”
This translation would make perfect sense, as Nargothrond was mainly populated by Noldorin elves.

Taking into account that the area of the Narog river was populated with petty-dwarves long before the elves ever set foot there, it would possible that Petty-dwarves referred to themselves as “moon-dwarves”. It seems logical that the Petty-dwarves would not refer to themselves as “petty”, so why “moon dwarves” ?

The elves that arrived later at the Narog river couldn’t have given them the name either, as they hunted the petty dwarves to extinsion, not knowing they were related to dwarves at the time.

Well, I believe I might have another idea…

After the Darkening of Valinor and the destruction of the Two Trees, Telperion, the White Tree, bore one last Flower of Silver before its end (which was the moon). According to the lore of the Elder Days, Mahal (Aulë) and the dwarves made a vessel to carry to the silver flower aloft, and Tilion, one of the hunters of Oromë; was granted the task of steering the new Moon through the sky.
So, without Mahal and the dwarves, the moon wouldn’t be in the nightsky.
Now, what does this have to do with the Petty-dwarves ?

Well, firstly we need to look at when this happened… and we find a remarkable piece of information, which is that it coïncides with the existance (and exile) of the petty-dwarves.

It is written that the petty dwarves were banished for “various reasons”, although not clear for which reasons exactly. One theory is that the Petty-dwarves were banished because they spoke Khuzdul freely and gave away the secrets of their language and names, which could indeed have been the case (but only accounts for one reason). However, taking into account the above I believe there is another reason…

My theory is this…
I believe that some dwarves actually took credit for the creation of the moon, not just assisting Mahal by putting it at the nightsky, but claiming it’s actual creation.
For this Mahal punished them by making them physically smaller and giving them bodily deformities. These dwarves abandoned Mahal and his laws and started speaking Khuzdul openenly, giving their inner names away to all. As a result Mahal (or the other dwarves themselves) banished this group of dwarves.

This would account for being banished for “various reasons”. It also explains why these dwarves did not follow Mahal’s rules of Khuzdul secrecy (as they were holding a grudge due to being made smaller and deformed). Also, the name of “petty-dwarves”, I believe “petty” doesn’t just mean small, but means “of little importance” (like in 16-century english). Which generally would be the case for people that have been banished, they would be labled “of little importance” – as you would normally not speak of those that have been banished out of respect for the ruler that banished them. Hence, I believe we’ve found a reason why these dwarves were referred to as “petty”.

Now, if we hold this theory to be true and we consider the position of the Petty-dwarves from their point of view, I believe it would make perfect sense they would refer to themselves as “moon-dwarves”. Think of it, you’ve been made smaller, deformed, banished… all because you didn’t agree with your creator. So chances are pretty high you would still be holding a grudge and wouldn’t simply give up your claim of moon creation… on the contrary (knowing how headstrong dwarves can be), you’ll likely hold your head high, denounce Mahal alltogether and call yourself “moon-dwarf”.

That’s my theory … just a theory off course. And as petty-dwarves are extinct (and the man that invented them no longer lives) I guess it will remain a theory.