BACKGROUND/AIMS: This study investigates a possible merger in the early stages between /i:/ and /y:/ among young speakers in Gothenburg, Sweden.

METHODS: (1) A large-scale online perception experiment testing listeners' abilities to identify the two vowels and (2) acoustic analysis of 705 vowels from 19 speakers.

RESULTS: The perception study shows that listeners classify the horizontally centralized /y:/ as /i:/, both in isolated vowel items and in items containing the full word. This indicates that /y:/ is moving into the perceptual space of /i:/. Listeners also classify the unmerged /y:/ as /i:/ when listening to [y:] in isolation, indicating that lip rounding is a perceptually weak feature, for this centralized vowel, in this variety. The acoustic analysis shows that /i:/ tends to be produced as [ɨ:], and that there is no acoustic difference between /i:/ and /y:/ in measurements correlated with the first two formants, i.e. lip rounding is the most important distinctive feature.

CONCLUSION: Results point in the direction of an incipient vowel merger, following a merger-by-approximation model. These results indicate a lack of perceptual strength of an articulatory feature in the disappearing phoneme, namely lip rounding, and the consequent perceptual similarities between the horizontally centralized [ɨ:] and /y:/.