Multilingualism is an international fact of life and increasing in the United States. Multilingual families are exceedingly diverse, and policies relevant to them should take this into account. The quantity and quality of a child's exposure to responsive conversation spoken by fluent adults predicts both monolingual and multilingual language and literacy achievement. Contexts supporting optimal multilingualism involve early exposure to high quality conversation in each language, along with continued support for speaking both languages. Parents who are not fluent in English should not be told to speak English instead of their native language to their children; children require fluent input, and fluent input in another language will transfer to learning a second or third language. Messages regarding optimal multilingual practices should be made available to families using any and all available methods for delivering such information, including home visitation programs, healthcare settings, center-based early childhood programs, and mass media. [This issue of "Social Policy Report" also contains: "The Specificity Principle (SP) in Multiple Language Learning" (Marc H. Bornstein). Commentaries in this issue are: (1) "Promoting Positive Development among Young Multilingual Learners" (Lisa M. López); (2) "'Pickney Talk Sweet, eh?' Unpacking Myths and Best Practices for Black Children Who Speak Creoles or Dialects" (Stephanie M. Cureton); (3) "Peering through the Looking Glass with a Multicultural Lens the Challenge of Translational Research" (Michael L. López); and (4) "Multilingual Children Developing and Disseminating Knowledge to Support Successful Language Development" (Diane August).]