In a letter to the British newspaper The Observer written in 1938, Tolkien wrote regarding the name of the dragon Smaug:
The dragon bears as name — a pseudonym — the past tense of the primitive Germanic verb smugan, to squeeze through a hole: a low philological jest.
To clarify his meaning: there was, or can be assumed to have been based on descendant languages, a proto-Germanic verb smûgan, meaning “to creep, to crawl, to go through a hole,” of which the 1st person and 3rd person singular forms of the preterite tense would have been smaug: “I crept/he, she, it crept”.
Why this derivation would be humorous, even to philologists, let alone a “low jest” is, I suppose, something for the reader to guess at. It’s not even clear why it’s relevant to Smaug as a character — other than that a dragon can be considered a kind of serpent, and serpents creep — since one of the things we know about Smaug is that he was too large to “squeeze through a hole” as large as five feet by three. However, this particular Germanic root was a favorite of Tolkien’s — it also appears in Gollum’s proper name, Sméagol (Hobbitish Trahald, which Tolkien translates as “burrowing, worming in,” but which in light of Old English sméagend might also be rendered “searcher, investigator,” both being plausible descriptions of Gollum) and in the large delvings built by more prosperous hobbits, smials (from Old English smygel “burrow”= Hobbitish trân < trahan).
This sort of “jest” is not at all untypical of Tolkien’s linguistic work. From the very beginning of his invention of languages, the vocabularies are rich with “puns” — of a sort. They are plays on words that usually require some knowledge of other languages, modern, historical, and reconstructed, to be understood. They are not, as a rule, more humorous than needed to crack a very slight smile on the face of the person who gets them; and, like all puns, they lose their humor once explained. Some of these have been fairly thoroughly documented by Tolkien himself; for instance, the origin of orc in Latin orcus “underworld” (Late Latin “demon, ogre”); or of Eärendil in Old English Earendel, apparently a figure or concept from Germanic mythology associated with stars or with the dawn. But there are many other words, not bearing any particular mythological importance, which are borrowed, with more or less change, from various languages. To list them all would be a great labor. But derived from Finnish, for instance, we have the Elvish words rauta “metal,” tie “road,” lapse “baby,” kulu “gold”; from Primitive Germanic mat- “eat,” suk- “drink”; from Greek aglar “glory,” pen “lacking”; from Latin vala “have power,” ros “dew, spray,” cassa “helmet”; from some Slavic language ranko “arm”; from Hebrew pé “mouth.” These are only some of the ones I can think of off the top of my head. Some of these “puns” are indeed far too obvious, such as (in an early vocabulary) nénuvar “pool of lilies”, from French nénuphar “a water-lily”! Tolkien tended to drop some of the more obvious puns from his Elvish vocabularies, and was occasionally concerned (unnecessarily, I think) about too-obvious resonances between Elvish and real-world languages. For instance, it seemed to concern him that the Elvish negative element ú resembled too much various derivatives of Germanic un-, like Old Norse ó-, ú-. He occasionally considered replacing it with the element lá — forgetting, perhaps, that lá itself closely resembled the Arabic word for “no” or “not”, lâ!
Tolkien also repeatedly engaged in several “low philological jests” between his own languages, a sort of cross-pollination. Adunaic naru “male” echoes Quenya nér of the same meaning (though both probably echo Greek anêr, Sanskrit nara; and, for that matter, Adunaic zini “female” echoes, at a greater distance, Greek gynê, Persian zan). Adunaic mânô “spirit” echoes Quenya manu “departed spirit”. Khuzdul kibil “silver” echoes Sindarin celeb of the same meaning. Adunaic târik “pillar/that which supports” may be echoed in Khuzdul tharkûn “staff-man” (a nickname of Gandalf).
I’m discussing this because it relates to how I went about building Khuzdul vocabulary. Coming up with sequences of sound to fit meaning is not an easy task. Language creators have gone about this in different ways. Some, like the makers of Esperanto, Interlingua, and other auxiliary languages, have drawn extensively on real-world languages to provide a basic vocabulary. Others, especially creators of “artlangs” (in which class I suppose neo-Khuzdul belongs) have tried to distance their languages from the real world context — which only makes sense if your language is supposed to be spoken on, say, an alien planet or in a parallel plane of existence. Some have gone so far as to use computers, programmed with certain limitations on sounds and word-types, to generate new vocabulary.
I couldn’t do that. To me, the junction of meanings and sounds has to make some sense, to me if not to others. Such ‘sense’ is usually derived from our own linguistic experience. If I were looking for a word for “round”, no doubt sequences that resembled RND or BL or GLB would seem more plausible than, oh, KZT or ShRG. There is also a certain amount of sound-symbolism which is, if not universal, at least common enough to be drawn on in language-creation. If I create the words bulmo and rizek, and tell you that one refers to sharp, brittle shards while the other refers to a large, soft pillow, few people — certainly few speakers of English — will have difficulty guessing which meaning belongs to which word.
Considering this, and considering that Tolkien’s languages were not examples of pure language-making, untainted by influences from outside, I decided not to consciously avoid “influences,” either from real-world languages or from Tolkien’s languages, but to take them as they came to mind, and consider whether they could be fitted to the sound-patterns of Khuzdul. Neo-Khuzdul is therefore full of linguistic “puns” and references, though these are for the most part limited to the particular choice of sound-sequences for the roots.