Two invented languages of Kurtish and of Laeglish both obey principles

Official Explanation

Your task is to find one word that can be a Laeglish word but not a Kurtish word, as well as another word that cannot be either a Laeglish or a Kurtish word.

In both cases, the word cannot be a Kurtish word, so start there. In Kurtish, any one word can contain either the brutish vowels (a, o, and u) or the fragile vowels (e and i), but not both. Which words fail this constraint?

calzral: only a, brutish. Passes.
fip: only i, fragile. Passes.
apheitso: both brutish (o) and fragile (e and i). Fails; this one can’t be Kurtish.
brueshmen: both brutish (u) and fragile (e). Fails; this one can’t be Kurtish.
qudxatroua: only brutish (a, o, and u). Passes.
hzziigri: only fragile (i). Passes.

So the two answers must be either apheitso and brueshmen, as these are the only two that fail the Kurtish requirements. One of these could be Laeglish; the other cannot. Next, apply the second constraint: a Laeglish word can contain both types of vowels, but the different types cannot touch each other in the word. These two words contain both types of vowel (based on the first pass through the answers), so which one fails the Laeglish test?

In the word apheitso, the brutish vowel (o) does not touch the fragile vowels (e and i), so this word could be a Laeglish word (even though it cannot be a Kurtish word).

The word brueshmen, on the other hand, contains a brutal vowel, u, that touches a fragile vowel, e. This word cannot be Laeglish, nor can it be Kurtish.

Column 1: The correct answer is C.
Column 2: The correct answer is D.