Stress Pattern Preference in Spanish-Learning Infants: The Role of Syllable Weight.

As a result of exposure, infants acquire biases that conform to the rhythmic properties of their native language. Previous lexical stress preference studies have shown that English- and German-, but not French-learning infants, show a bias toward trochaic words. The present study explores Spanish-learning infants' lexical stress preferential patterns and the role of syllable weight at 9 months of age. Spanish is a syllable-timed language with no vowel reduction and variable stress. Around 50% of the word types in Spanish are disyllabic, with a superior proportion of trochees than iambs (60% and 40%, respectively). Experiment 1 with CV.CV pseudo-words failed to reveal a clear trochaic bias in 9-month-old Spanish-learning infants. However, when preference was explored with items containing a heavy syllable (CVC.CV and CV.CVC, respectively), both a trochaic (Experiment 2) and an iambic preference (Experiment 3) could be elicited. These results suggest that knowledge about the close and highly regular link between heavy syllables and stress assignment in Spanish can be easily acquired and determines infants' preference at 9 months of age, while for CV.CV items, the trochaic bias appears to be weak. Our results broaden the current knowledge on the factors that determine the emergence of rhythmic biases.