Vowel harmony is not an answer key in a Turkish word game. It is a practical ranking signal: the front-back and rounded-unrounded relationships among confirmed vowels can strengthen some candidates and weaken others, while loanwords require players to preserve room for exceptions.
What major vowel harmony suggests
The general expectation is that a back vowel in the first syllable is followed by back vowels, while a front vowel is followed by front vowels. The Turkish Language Association overview of major vowel harmony explains the rule and common categories of exceptions. When a guess confirms a front vowel, that expectation can help rank the remaining vowel choices.
Why it is not a hard filter
Not every Turkish dictionary word follows major vowel harmony. Loanwords, compounds, and historical sound changes can break the regular pattern. A player should therefore lower the priority of a disharmonic candidate rather than deleting it automatically. Explicit letter feedback remains stronger evidence than phonological intuition.
How to apply it in a round
First classify the confirmed vowels as front or back. Next list standalone dictionary words that match the known positions. Try harmonious candidates early, while retaining plausible borrowed words. A useful next guess should not only chase the answer; it should also test unresolved vowel possibilities efficiently.
This method does not expand the target pool to arbitrary inflected forms. A candidate must still be a standalone word, which can be checked in the Turkish Language Association dictionary.