The obscure auxlang Neo is known for how short its words and sentences always are. The language favors mono-syllabic words, and looking at sample sentences its rare for a word to be more than 4 or 5 phonemes long.
I've always wanted a conlang that didn't take long to say things, but how short can things actually get before they become impractical? Languages need redundancy, obviously, and its assumed that natural languages have the minimum amount of redundancy necessary. I can't fathom how to replicate something like this in a conlang.
The only other 'short' language I know of is Ithkuil and its various derivatives. That language can easily fit an entire sentence into a single 'word'. In fact, morphemes are often just a single phoneme long! The name of the language itself is actually made up of 4 morphemes (or more depending on how you count them). The morphemes are i-, -th-, kul, and the infix -i- (here its inside the 'kul' morpheme). Obviously, a language like this wouldn't be practical in reality. You could literally miss an entire 'word' of a sentence if you fail to hear even a single phoneme! Not to mention this conlang uses a ridiculously huge phoneme inventory to maximize its number of short morphemes; the original version effectively used the entire IPA, though the latest version now uses phonemic tone and a far more reasonable phoneme inventory. With the original version, only someone who could pronounce and easily distinguish every single symbol in the IPA could possibly speak this language. And of course, the author just made this as a thought experiment, he didn't intend anyone to actually use it.
So this has me wondering: how short is too short? Neo actually looks to be shorter in expression than English, though that's hard to say since the language never became popular. As far as I'm aware, there's never been any kind of extensive text translated into the conlang. Also, the conlang features a VERY generous number of derivational affixes that puts even Esperanto to shame. I highly suspect the possibility of long-winded compound words is there.
Also, how do you measure shortness? Is a morpheme with a CCVC structure shorter than a CVCV word?
And it is clearly possible for some languages to take longer to say things than others. If you watch some Spanish-speaker giving a speech, its pretty obvious that it takes him longer to say things than it would take to say the English translation (not to mention on average, Spanish words tend to use far more phonemes than their English translations). And of course Japanese is highly prone to being long-winded. I mean, their primary word for 'I' is 6 phonemes long! And their verb endings can easily add 4 or more phonemes to the end of each sentence, and very often do (Korean I believe is also infamous for the long chains of suffixes that can often appear on verbs). Its also obvious that Piraha takes longer than normal to say things, though that appears to be mainly a consequence of the fact that it doesn't allow adjectival clauses.
Is there really any measuring stick you could use to determine this? I've noticed that English seems to have a reputation for being short, though I'm not sure if its the shortest. Mandarin seems to have far more short syllables on average than English does, and that's going by the average number of phonemes per word. Personally I was thinking of using my own native language as a measuring stick: if a word has a number of phonemes equal to or less than its English translation, then its short. Of course, translations aren't normally that short forward, plus I've noticed that English seems to really like to use affixes that are only one or two phonemes long (our plural, possessive, and past tense endings are all a single phoneme, barring the occasional epenthesitic vowel). Even our auxiliary verbs and pronouns tend to be just two or three phonemes long, which thinking about it is rather hard to match, especially if your conlang has a smaller phoneme inventory than English.