A few days ago (from when I first made this) I learned that the Cursed Conlang Circus (which I'd seen some submissions to on YouTube) was happening again this year, and then found out it was too late to submit anything, but I had an idea, so I'm making it anyways, because conlangers don't care what humans think is impossible. (I did submit something, not sure if it will be accepted. Version I submitted; video I made.)
Leckna, which can be pronounced /ˈleu̯ŋ.knai̯a̯/ and can be interpreted as "can speak", is an international auxiliary language.
⟨l⟩ is the "whatever lambdic", which, depending on what you're comfortable with, can be pronounced /l/, /ʎ/, /ɫ/, /ɺ/, /ɬ/, /ɮ/, /ǁ/, or anything else, as long as it's lateral.
Vowels
To make things simple, Leckna has a 3-vowel system. Since the two most widely-spoken languages, English and mandarin Chinese, use diphthongs, the Leckna also uses diphthongs, which should make it easier for speakers of those languages. Its vowels are
Front
Back
High
e /eu̯~ue̯/a /ai̯a̯/o /io̯~oi̯/
Mid
Low
Or, in other words:
e /eu̯~ue̯/
a /ai̯a̯/
o /io̯~oi̯/
To make it even easier, in case some diphthong is hard to pronounce, it can be reversed with no change in meaning. For instance, "po", meaning "bee", can be pronounced /poi̯/ or /pio̯/.
Tone
Since the language with the most native speakers, Mandarin Chinese, has tone, to make it easier for them, Leckna also has tone.
Leckna has two types of tone: level and contour. Level can be high or low, and contour can be rising or falling, depending on what's more comfortable to the speaker and what sounds the best. Contour tone is marked in the spelling with a diacritic; since not everyone has the same keyboard layout, it can be any diacritic, whichever is easiest for you to type.
Syllable structure
Leckna's syllable structure is C(C)V(C).
Syllables may start with a single consonant or a cluster of two consonants. Consonant clusters must be different manners of articulation, but otherwise can be any two consonants; this keeps things simple, so speakers don't have to memorize any complicated phonotactics rules. Like with diphthongs, the consonants in a cluster can be swapped without changing the meaning, so e.g. ksá and ská are the same word (both meaning "sky").
The cluster /ks~sk/ can be spelled ⟨x⟩. There is no pattern to when it's spelled that way vs. when it's spelled ⟨ks⟩ or ⟨sk⟩. Aside from words that must be spelled with an ⟨x⟩, speakers are free to write the consonants in a word in whatever order they want.
Syllables can end with a consonant or not a consonant. If they end with a consonant, the consonant is unspecified for place of articulation, voicing, and manner of articulation; it can be whatever consonant the speaker finds easiest to pronounce. This unspecified consonant is spelled ⟨c⟩, since that letter can be used for so many different sounds across different languages (and even within one language).
Vocabulary sources
To make it easier for speakers of other languages to learn, all vocabulary is derived from the top one most widely spoken languages. If the majority of the source languages don't agree on something, then all the words are put into a super-secret magical phonetic averaging algorithm; even I don't know how it works. I then try to squeeze it into the phonology and phonotactics of Leckna.
Grammar
Sentence-level
Word order can be any of SOV, SVO, VSO, VOS, OVS, or OSV. Which word is the subject and which is the object are deduced from context. This makes the language easier to learn for speakers of languages with any word order.
Words like fó ("if") and xá ("because") can go before or after the dependent clause, and the dependent clause can go anywhere in the sentence.
There is no word for "to be"; just put the noun and noun/adjective/etc. next to each other with no verb in between.
Nouns and noun phrases
Nouns are not marked for case, number, or definiteness, and have no gender, to make thing easier for speakers of languages that don't have those features. Those are derived from context.
Adjectives can be placed before or after the noun they modify. Similarly, genitives can be placed before or after the noun they modify, and there's no extra marking to show that the noun is a genitive.
Pronouns are 'a for anything that includes the first person (including any sort of "we"), 'e for anything that includes the second person (including inclusive "we"), and 'o for anything third person. Pronouns can be omitted if it's clear from context who or what you're talking about.
Verbs and verb phrases
Verbs are not marked for tense, aspect, mood, or negation. All of those are deduced from context.
That last one, negation not being marked, has an added advantage that in Leckna, it's impossible to lie (and, in fact, this is the meaning of the name: lec = lie, kna = can't, so "can't lie"). Take, for example, the sentence "I have a cat":
'a ha ka 'aIhahavekacat
If it turns out this is false, then that's totally fine, since you could have also said this, which means "I don't have a cat":
'a ha ka 'aIha-∅have-negkacat
Numbers
Leckna uses base 10. The digits are as follows:
1
oc
2
te
3
flo
4
flo
5
fac
6
ksoc
7
sefe
8
oc
9
nac
For longer numbers, just put the digits in order. For zero, just say nothing for that position.
Words
'a
I/we
'á
all
'e
you/we (inclusive)
'fa
off, from, onto
'o
he/she/it/they
fac
five
flá
fly, flight, aviation
flo
floor, ground
flo
four
flo
three
fné
enough, too
fo
this, that
fó
if
ha
have
hme
human, person
ka
cat
kloc
green
kna
can, be able, possible
kné
wing
kno
know, understand
ko
care
ksá
sky
ksoc
six
lá
law (legal or physical)
lec
say, speak, lie
Leckna
Leckna
leckó
language
lelo
yellow
nac
nine
oc
eight
oc
one
Ockloc
English
pa
by, according to
pfó
obviously
ple
blue
po
bee
poto
body
sefe
seven
smac
small, big
soc
should
te
two
tfa
skinny, fat
the
head, think
tlé
red
xá
because, cause, make
Examples
Do you speak English?
'eyoulecspeakOckloc? English?
I speak English.
'aIlecspeakOckloc. English.
I don't speak English.
'aIlecspeak-negOckloc. English
According to all known laws of aviation, the bee should be able to fly.
According to all known laws of aviation, the bee shouldn't be able to fly. Its wings are too small to get its fat little body off the ground. The bee, of course, flies anyway. Because bees don't care what humans think is impossible.
Pa 'á kno lá flá, po soc kna flá. 'o kné fné smac xá tfa smac poto 'fa flo. Po pfó flá xá fo. Xá po ko hme the kna.
The main idea was one that I had for a long time, but never intended to make into an actual conlang: specifically it was the "can't lie"/null negation thing. I tried to choose other aspects of the language that would go with that, but given the final product, it kind of feels like that aspect has less prominence than what I was originally going for.
I made it an "auxlang" partly because "a priori" was one of the themes of the circus, and partly because it made things easier given the short amount of time I had to make the language. This is very different than my original intent for this idea, which was an alien language; my original idea was that the aliens in some sense don't care about reversing things, which would appear both in the whole negation thing and also in other places. In the final language this ended up with reversing the word order and reversing certain sounds in a word not changing meanings (which I justified with making it "easier" for speakers of different languages), but my original idea also had reversing the sounds in entire words and reversing glyphs in the writing system (which this was originally going to have) also not changing the meaning.
I also didn't really explain how you could still communicate with negation not being expressed, which was part of my original idea...
Is this cursed enough in the right way for this? I don't know. I hope so.
and can be interpreted as "can speak", is an international auxiliary language.