Biliteracy Education Seal and Teaching Act or the BEST Act This bill directs the Department of Education to award renewable two-year grants to states to establish or improve, and carry out, Seal of Biliteracy programs and early language programs to recognize student proficiency in both English and a second language. Student proficiency shall be demonstrated through proficiency in speaking and writing in both languages and may also be demonstrated through reading and listening in both languages. Further, these programs must allow speakers of any official Native American language to use equivalent proficiency in speaking, reading, and writing in such language in lieu of proficiency in English.