Final answer:
The culture groups significant in the history of Early Childhood Education with lesser-documented contributions are African American, Hispanic, and Asian.
Step-by-step explanation:
The three culture groups that played significant roles in the history of Early Childhood Education, although their contributions are not well-documented, are African American, Hispanic, and Asian. These cultural groups have faced various challenges throughout the history of the United States, such as segregation in schools, and have had to fight for equal educational rights and opportunities. Despite these challenges, each group has had an impact on Early Childhood Education through their socio-cultural contributions, community values, and advocacy for bilingual and multicultural education.