The phonetic characteristics of canonical babbling produced by Korean- and English-learning infants were compared with consonant and vowel frequencies observed in infant-directed speech produced by Korean- and English-speaking mothers. For infant output, babbling samples from six Korean-learning infants were compared with an existing English babbling database (Davis & MacNeilage, 1995). For ambient language comparisons, consonants and vowels in ten Korean and ten English infant-directed speech (IDS) samples were analyzed. The two infant groups demonstrated similar consonant patterns, but showed different vowel patterns from one another. For both languages, infant vowel patterns were related to those of ambient language IDS. Ambient language patterns were manifested in infant vowel output, perhaps because vowels are more perceptually and motorically available in the input and output capacities of babbling infants.