Not terribly long after starting up, Semantic Compositions managed to ruffle some feathers by talking about fictional languages and contrasting the effort spent on them by their devotees with the efforts currently going into archiving dying languages. At the time, your host held a rather dyspeptic view of fictional languages, in no small part due to brutally effective satires like this.
However, aside from the sorts of people who spend dozens of hours putting together elaborate costumes and spending entire weekends at fan conventions (while living in their parents' basements otherwise), there are also people out there who are both serious students of linguistics and able defenders of fictional language research. In particular, Rachel Shallit managed to convince SC that he was too quick to be dismissive, not only with her initial comment about how Tolkien brought her to an interest in linguistics, but by backing that up with applications of Optimality Theory, as well as with a perfectly serious discussion of how to say "I love you". While SC couldn't read her OT-based paper, the argumentation in the latter post demonstrated convincingly that one could talk seriously of attested examples and underlying forms in a well-thought-out fictional language.
This came up again yesterday when SC received an e-mail from Qov, who maintains one of the few (the only?) blogs written entirely in Klingon. SC readers will recognize her as a frequent commenter here, as well as at some other language-related blogs. Qov wished to respond to your host's original post by explaining: 1) how she personally got into the study of Klingon, and 2) how serious an endeavor it actually is. Having gotten permission to quote her e-mail, I'll post some of the relevant parts, along with a few responses:
I grew up as an anglophone (is that word in use in non-French-speaking countries?) in Vancouver, Canada. I was fascinated by languages, and wanted to be a UN interpreter. I took French in school, learned a bit of Esperanto from books and a course I convinced my mother to drive me to, learned a bit of Russian from the encyclopedia and my mother's souvenirs, signed up for Latin in high school but was the only person interested, so took two years of Spanish instead.
At university I majored in Chemistry, and minored in Russian language. At the time I was a fanatical Star Trek fan, and a friend spotted a Klingon dictionary in the bookstore, giving me a new hobby.
Here was a language I could completely learn: this was it, here, the entire vocabulary in my hands, and a grammar like nothing I'd ever seen before. I learned the grammar, and then when I discovered there were other people who played with this toy I did memorize the vocabulary and have had good conversations with the terrifyingly brilliant men who translated Hamlet.
This seems to be further confirmation that fictional language learners aren't just the sorts who have spent a few too many hours standing in line for the latest Star Wars (SC supposes this can be forgiven for The Phantom Menace, because nobody knew, but not for Attack of the Clones). Qov's got significant training in more languages than SC does, not to mention a fair number of academic linguists.
Most of the more accomplished Klingonists count Klingon as one of many languages they speak. Of the four people who worked on Hamlet, I believe two have linguistics PhDs, and another is working on a doctorate in computer science and cognitive science, and counts Basque and Welsh among his other hobby languages. I think it would be more accurate to say that Klingon motivates us to work on other languages than that it wastes time we could have spent on other languages.
To be honest, SC had suspected that the difference between Tolkien's languages and Klingon, Romulan, or any other sci-fi/fantasy language was that Tolkien was alone in being linguistically sophisticated. This was an opinion based entirely on...well, unsubstantiated opinion. More on this point later.
There is another set of Klingon speakers who are interested in it just for its connection to the television shows...They achieve varying degrees of success but persist, because they are in a supportive community of Klingonists. It's unlikely that this group of people would ever succeed in learning a dying language to an extent that would do anything about its preservation.
This is an eminently fair rejoinder to my original complaint that resources are somehow being diverted from studying endangered languages. It's not a case of economic substitution; were it not for Klingon, some people would have no linguistic interest at all.
Klingon does encourage people to do things with language that they would not otherwise do. The Klingon Bible translation project you may have heard of is progressing extremely slowly, because the translators are working from the original. This of course promotes knowledge of Greek and Aramaic as well as Klingon.
Can't really argue with this endeavor, either. Less serious people who were just looking to rush something out to sell to interested Star Trek fans would have started from some reasonably well-accepted English translation.
Memorizing Klingon is heavily disparaged, in a way that memorizing sports scores or the attributes of different models of car never is. The time-wasting aspect is often cited, but surely it beats out watching daytime TV, which never incites such hoots of derision.
As SC replied to Qov directly, guilty as charged. Your host has spent more hours than are decent in reading and rereading the annual Car and Driver buyers' guide, as well as that published by Home Theater. It's disturbing to think how much better SC's knowledge of Japanese (which I speak/read like a 3-year-old, or an American college student) could be if he applied that time to studying kanji instead. More broadly, though, your host's original opinion -- and that of many others, he suspects -- has been a matter of not being able to distinguish the activity of learning Klingon from just sitting around watching Star Trek. But learning any language is more intellectually stimulating than watching TV, and surely it's an act of hypocrisy to look down on such efforts unless you're doing something more productive.
So, having seen what people who study fictional languages are really like, SC will cite John Maynard Keynes, who famously said "When the facts change, I change my mind - what do you do, sir?". Consider SC's mind changed.