The objective of the study is to find out the effects of toddler's temperament and mother's parenting
behavior on the development of vocabulary ability. The study was conducted with 299 infants between
the ages of 18 and 24 months and their mothers in 47 day care centers in I city, Jeollabukdo. The results
of the study are as follows. First, according to the correlation between infant's temperament and
vocabulary based on the composition of temperament, approach-avoidance, adaptability, and mood showed
a negative correlation with receptive and expressive vocabulary, and response intensity showed a positive
correlation with receptive vocabulary. Second, according to the relation between mother's parenting
behavior and infant's vocabulary ability based on the sub-factors of mother's parenting behavior,
instructional parenting behavior and setting-limits parenting behavior showed a positive correlation with
receptive and expressive vocabulary. Third, according to the effects of infant's temperament and mother's
parenting behavior on the development of infant's vocabulary ability, as for the understanding of
vocabulary, the explanation power of approach-avoidance is the highest, followed by instructional
parenting behavior, response intensity, and mood. As for expressive vocabulary, the explanation power of
instructional parenting behavior is the highest, followed by mood, response intensity and activity. In the
development of infant's vocabulary ability, it was found that receptive vocabulary was affected the most
by approach-avoidance, and expressive vocabulary was affected the most by instructional parenting
behavior. Mothers will have to have interrelation skills suitable for temperament for the development of
infant's receptive vocabulary, and have parenting behavior expressing the traits of things and events for
the development of expressive vocabulary.