Articulatory complexity, ambient frequency, and functional load as predictors of consonant development in children. 
The notion of a universal pattern of phonological development, rooted in basic physiological constraints, is controversial, with some researchers arguing for a strong environmental (ambient language) influence on phonological development or an interaction of both physiological constraints and ambient language effects.  This research examines the relative value of articulatory complexity, ambient frequency, and functional load as predictors of consonant development in children.  Three languages are investigated: Cantonese, American English, and Dutch.  Regression analyses revealed that functional load accounted for 55% of the variance in age of emergence of consonants in 7 English-speaking children (8-25 months), while frequency of consonants in the ambient language accounted for 63% of the variance in age of emergence of consonants in 51 Cantonese-speaking children (15-30 months).  Articulatory complexity accounted for 40% of the accuracy of production of consonants in 40 English-speaking children (25 months), and frequency accounted for 43% of the variance in accuracy of production of consonants in 5 Dutch-speaking children (24 months).  Given cross-linguistic differences, further research is required.