NACLO 2025 - Problem OI Speak, Therefore I Am

Patricia speaks Tuyuka, so (4) = Y. The mother of Aldine, Emilia, speaks Kotiria, so (1) = K (also Agostinho speaks Kotiria). If Agostinho doesn't understand Tariana, then (3) is not Tariana, leaving only (3) = T. Therefore (2) = R.

Now for O2 and O3. O3 tells us that we can't match the statements completely to speakers, but I'd still like to match the translations to their speakers, so it tells us what language each one is spoken in. The 7 speakers' languages are as follows:

Speaker	Patrilect	Matrilect
Cagüü̃cü	Tukano	Tuyuka
Mayẽ	Tariana	Tukano
Elizabete	Kotiria	Tukano
Fausto	Kotiria	Tuyuka
Elsa	Kotiria	Tuyuka
Lucas	Tukano	Kotiria
Kaly	Tariana	Kotiria

The starting point is sentence C, which sufficiently resembles Aldine's statement differing only in the name of the language, so it's probably "My mom speaks ____" in Tukano where the blank is something other than Kotiria. The only speaker who speaks Tukano and has a matrilect other than Kotiria is Cagüü̃cü, so sentence C must be said by Cagüü̃cü, meaning vii "My mom speaks Tuyuka".
The other Tukano speaker, Lucas, must have said iii "I speak Tukano".
Lucas's matrilect is Kotiria, so sentence v "My mom speaks Kotiria" must be said by Kaly, the only other person with matrilect Kotiria.
Kaly speaks Tariana, so sentence ii "I speak Tariana" must be said by Mayẽ.
Mayẽ's matrilect is Tukano, so the other person with matrilect Tukano, Elizabete, must have said vi "My mom speaks Tukano".
The remaining 2 speakers are Fausto and Elsa, who both speak Kotiria and understand Tuyuka. The remaining sentences are i "I speak Kotiria" and iv "I understand Tuyuka", which are both in Kotiria.

We already know the following:

Sentence	Patrilect	Matrilect
i (Fausto/Elsa)	Kotiria	Tuyuka
ii (Mayẽ)	Tariana	Tukano
iii (Lucas)	Tukano	Kotiria
iv (Fausto/Elsa)	Kotiria	Tuyuka
v (Kaly)	Tariana	Kotiria
vi (Elizabete)	Kotiria	Tukano
vii (Cagüü̃cü)	Tukano	Tuyuka

We can continue matching translations with their original sentences:

E "Yʉ Tuyuka thʉ’oha" mentions "Tuyuka". Sentences iv and vii involve Tuyuka, but vii is already matched to C, so E must match to iv "I understand Tuyuka", which is in Kotiria. Indeed, this sentence resembles Agostinho's statement in Kotiria "Yʉ Phaana thʉ’oeraha", meaning "I do not understand Tariana".
According to Emilia, Tukano is called "Dahsea" in Kotiria (I realized much later that capitalized letters in the transcription are language names). A "Yʉ phʉkoro Dahseakoro hira" also mentions "Dahsea". Sentences iii and vi involve Tukano, but only vi is said by a Kotiria speaker, so A must match to vi.
At this point, 2 sentence that begin with "Yʉ" are both identified to be Kotiria, so the third one, sentence D, is very likely to be Kotiria as well, which would match to i "I speak Kotiria". Indeed, D also mentions "Kotiria".
If the above logic works, then we should similarly assume that the two sentences beginning with "Yɨ’î", C and F, are both Tukano. So iii matches to F.
We have B "Nohá Taliá yarupe nu-tsaápeni-noka" and G "Nohádoa Panumápe yarupe du-tsaápeni-noka" left, meaning ii "I speak Tariana" and v "My mom speaks Kotiria". The phrase for "I" should be shorter than "My mom", so B should match to ii (also because "Taliá" resembles "Tariana"), and G should match to v.

The statement of O3 tells us that "Yʉ Kotiriakoro hiha" is the feminine version while "Yʉ Kotiriro hiha" is the masculine version. Because D (= i) uses the former, it must be said by the female speaker Elsa. E (= iv) is therefore said by Fausto.

Now for O4 and O5. So far, we have the following Kotiria sentences:

Yʉ Kotiriakoro hiha I (fem) speak Kotiria.
Yʉ Kotiriro hiha I (masc) speak Kotiria.
Yʉ Tuyuka thʉ’oha I (masc) understand Tuyuka.
Yʉ Phaana thʉ’oeraha I (masc) do not understand Tariana.
Yʉ phʉkoro Dahseakoro hira My mom speaks Tukano.
Yʉ phukoro Dahsea thʉ’oerara My dad does not understand Tukano.

The footnote says that:

In Kotiria, to "speak" is to "be"; "I am Kotiria" would be a closer translation than "I speak Kotiria"

Therefore, it seems that the "-koro" suffix is added to the language name in the context of "speak" but not "understand".

From 3 and 4, we know that negation is formed by adding "-era-" before the final "-ha". From 1 and 5, we know that the verb "speak" (or "be") is "hiha" or "hira" which agrees with the subject. Therefore "does not speak" is "hierara". 5 also tells us that "my mom" is "Yʉ phʉkoro". Joining them together, My mom does not speak Tuyuka. is translated as:

Yʉ phʉkoro Tuyukakoro hierara

If "My mom does not speak Tuyuka", then the matrilect of Ricardo is not Tuyuka. Since Ricardo's patrilect is not Tuyuka either, he doesn't understand Tuyuka. To translate I do not understand Tuyuka., just take sentence 4 and replace the language:

Yʉ Tuyuka thʉ’oeraha

Now for O6. At first I thought that the extra condition is that the two people's matrilects are also different, which is obeyed by every couple except Mayẽ and Elizabete. However, this means that for Lucas and Kaly, both of them can take either D or E, but the problem says there's a unique solution. Looking more closely, the condition can also be that the male's patrilect is the same as the female's matrilect (so the wife can understand the husband). Now the unique assignment is easy to find:

Fausto (speaking K) takes C.
Elsa (understanding Y) takes B.
Lucas (speaking T) takes E.
Aldine (understanding K) takes A.
Kaly (speaking R) takes D.

This also tells us that Sileia's matrilect is Kotiria.