Direct Translation

This is a crossword that uses the runic language from the game Tunic. Solvers might recognize this from having played the game before, or can find it by looking up the one clue in English, "SECRET LEGEND", which is the game's development title. The fox drawing at the bottom of the puzzle is also from Tunic.

The language consists of characters which represent sounds; each character has a consonant part and a vowel part. We can translate the clues manually or with an online translator tool, then fill the answers into the grid, also in the Tunic language. Note that characters in a word are assembled greedily, so a word like CAT will always be CA / T rather than C / AT. This gives the following completed crossword (written in phonetic English for easier reference):

Once this is done, the colored boxes form three matching color-related words reading top to bottom: CRIMSON, EMERALD, and AQUA. These correspond to the colored sections of the snaking path along the border. (Note that the border is symmetric across both sides; we'll focus on the left-side border, but the same logic applies if we choose the right-side border, only mirrored horizontally.) The next step of the puzzle is to realize that the border path encodes the Tunic characters for these words, where sections of the path from top to bottom represent the corresponding consonant or vowel sounds. This can be confirmed by noticing that the "k" sounds in CRIMSON and AQUA have matching path sections, and the schwa sound ("uh") appears the same in all three color words.

Using these three examples as well as the diagram at the bottom of the puzzle, we can figure out how the border language works. When tracing a path from top to bottom, we can track the sequence of four types of path segments, each made up of two straight lines meeting at a right angle. These are drawn in the fox's thought bubble at the bottom, and we can call them "down-right", "down-left", "up-right", and "up-left" respectively. For the border on the left side, down-right indicates that the next sound is a consonant, while down-left indicates a vowel sound. Then follows a series of up-lefts and up-rights, which can be interpreted as up-right for yes and up-left for no. Considering each segment of the Tunic character in the order indicated by the arrow in the bottom diagram, this tells us which segments of the character are present or absent.

For example, the first section of the red line is down-right, up-left, up-left, up-right, up-right, up-right. This represents a consonant character where the bottom-left and bottom-middle lines are absent, and the bottom-right, top-right, and top-middle lines are present; which is the character for the "k" sound in CRIMSON.

Finally, once we know how the border encoding works, we can look at the black section, which translates to ANSWER BARBADIAN SPEECH PATTERN.

Authors' Notes

Tunic is a fantastic game, and I found the in-game language really interesting. Unlike many other video game languages, it's not just a substitution cipher. This means a crossword using this language is fundamentally different from a crossword in English, and solvers have to consider translating the answers back into Tunic's language instead of just translating the clues into English and solving as normal.

The language also made the grid a challenge to construct - even with the leeway of unchecked squares, there are some pitfalls that were tough to avoid. It wasn't enough just to have the sounds match up, but crossings had to consider character groupings as well - CAT and CROW may share their initial "k" sound, but CAT starts with "ka" rather than just "k". There were also mistakes I made based on my own pronunciation of words: for VANGUARD, I originally wrote it as "va / ng / gar / d", but the typical pronunciation uses an "n" sound instead of "ng", which forced me to redo a large section in the southwest.

Despite these difficulties, I'm really happy with the final grid, since we were able to get a lot of fun fill along the way. There are a bunch of Tunic references in here, like in the clues for TUNIC, BOMB, HEXAGON, GARDEN, CANONICAL, and MANUAL. I'm also really happy with DOCKING SCENE (Interstellar is a great movie) and BYE BYE BIRDIE. Unfortunately, the STIR / ASTIR crossing in the northwest is less than ideal (it used to be SINE / ASSIGN but SINE can't start with an individual "s"), although I think the clues are different enough definitions that it's not a huge problem.

We tried to use the manual's spellings of words when possible, even when that differed from what one might expect, such as CANONICAL having an /ʊ/ sound in this solution instead of /ə/. This doesn't affect the solve at all, though, so using /ə/ is fine too.

The three colors for the border clues are a nod to the three colored hexagon keys that the player collects. The border cipher was also inspired by some of Tunic's late-game puzzles. I won't say anything more to avoid further spoilers, but if you've played the game, you probably know what I'm talking about. ;)

Appendix

Here are the translations and (non-phonetic) answers for all clues: