Answer:
The main or central idea of the passage is that learning a second language has multiple benefits and that certain states in the United States, such as California, New York, and Illinois, have taken steps to promote and recognize biliteracy through the establishment of a state "Seal of Biliteracy." The seals not only honor the significance of second-language learning but also serve as evidence for colleges and future employers of students' language proficiency.
Step-by-step explanation: