Developmental science recommends and national Head Start policy mandates incorporating Dual Language Learner (DLL) children's home language in classroom instruction. It is less clear, however, how this is implemented in the real-world context of early childhood classrooms. In four local Head Start centers in a predominantly Spanish-speaking DLL county, exploratory qualitative observations helped shed light on when the home language of Spanish was used in the classroom and how it may have contributed to DLL children's school readiness skills. Emergent patterns from the observations revealed that Spanish was used to promote certain academic as well as planning and recall skills; to provide emotional caregiving; and to communicate with parents as well as during daily health routines. Thus, in line with Head Start's "whole child" model, Spanish was used in the domains of academic, socio-emotional, and health development as well as to strengthen the home-school partnership. Implications for practice are discussed. (author abstract)