Recent findings suggest some properties of input in dual-language environments that influence its value for bilingual development, but the extant data base is small and sometimes inconclusive. The present study sought additional evidence regarding three quality indicators: the percent of input provided by native speakers, the number of different speakers providing input, and the frequency of language mixing. Participants were 90 thirty-month-olds exposed to Spanish and English. Using the Language Diary method to assess input and using multiple measures of children's bilingual skills, results replicated previous findings that the percent of input provided by native speakers is a positive quality indicator and found suggestive evidence that the number of speakers is also a positive quality indicator. There was little evidence that the frequency of language mixing is a negative indicator. These findings advance understanding of sources of variability in bilingual outcomes and have implications for programs to support bilingual development.