Those puzzles are fun to solve, so why not give them a try? Feel free to use this post to share hints or the solution as you’ve found it, but please use spoilers to do so.
The first three puzzles boil down to “retro-engineering” tidbits of the the grammar of three languages (Ubyx, Alabama, N|uuki). The fourth one is to deduce the words for familiar relationship used in Arabana. The fifth one is historical linguistics, deducing the sound changes from Proto-Chamic to Phan Rang Cham and Tsat.
Check this link for the puzzles of previous years, solutions, as well as versions in other metalanguages (in case you feel more comfortable solving them in another language than English).
A few hints for the first problem
Ubyx is agglutinative; words are mostly composed of morphemes being chained together. Try to identify what each morpheme means, by comparing words that are almost the same. Then use this new info to analyse the other sentences.
By the translation itself, you can guess that the verb should be split into at least four parts. Try to identify which ones, and in which order.