Long, long ago, in a post [at http://ozarque.livejournal.com/33721.html
] about the way extraterrestrial languages are usually handled in science fiction, I said:
What we ordinarily see is a language just like a Terran language except that it uses smells or colors or dance-movements instead of sounds. Or it uses many many glottal stops, which we write as apostrophes -- like, "Good morning!" T'k'l'p't said, in flawless X'gg'ta'l'nian. Or the writer devotes his/her attention to the writing system, which can be made Alien in a fashion that's impossible for speech, and says nothing about how the proposed language could be used for ordinary conversation. It's very difficult to find (in science fiction) a feature of a proposed spoken ET language that we can be certain does not occur in at least one human language. I can't offer you a single example of such a thing. But I would certainly welcome examples you may be aware of, so that we could discuss them.
"My Fith: http://www.langmaker.com/fith.htm
Years went by -- two of them -- and I have finally had time to go look at Fith, only to discover that it's a language so steeped in mathematics and computer science that if I had to use it I would be speechless. However, I found something I was
able to follow, and that I wanted to mention, from the "Fith Phonology" section at http://www.langmaker.com/fith.htm
... where ged
"A word is formed from the following components:
(I) V (F) H
I = Initial consonant or consonant cluster (optional)
V = Vowel or diphthong
F = Final consonant or consonant cluster (optional)
H = mandatory hand signal or word representing a hand signal"
Now that's interesting. This is -- as far as I know -- almost
an example of "a feature of a proposed spoken ET language that we can be certain does not occur in at least one human language." No human language -- as far as I know -- has a rule making it obligatory for every word to end with a hand signal.
The only reason I say "almost" is because "H" doesn't end at "mandatory hand signal." Because I'm not certain what "or word representing a hand signal" means -- especially the part about a word ending in a word -- I don't feel certain that no human language has that feature. If it means what I think it means, there could, theoretically, be a human language in which every word obligatorily ends in a sound segment or morpheme the meaning of which represents one or more members of a set of "hand signals." I don't know of any such language, but that doesn't mean there isn't one.
[Suppose the specification of "H" did
end at "mandatory hand signal" and I said here that I accepted that as "a feature of a proposed spoken ET language that we can be certain does not occur in at least one human language." That would be an audacious thing to say; usually, the minute a linguist says or writes or signs such a thing, the e-mails start pouring in with the information that human language X does indeed have that feature. I'd risk it this time, but would be fascinated to learn that I'm wrong.]