Conn. Agencies Regs. § 10-145d-475
This certificate shall be required for anyone employed by a board of education as a bilingual teacher as otherwise provided in Section 10-145d-610(m). Prior to July 1, 1993, an elementary certificate may authorize the teaching of the English component of the bilingual program in the grade levels of the elementary endorsement; a secondary English certificate may authorize the teaching of the English component of the bilingual program at both the elementary or secondary level; and a teaching of English to speakers of other languages endorsement (TESOL) may authorize the teaching of the English component at both the elementary and secondary levels. On and after July 1, 1993, the holder of a bilingual education endorsement or a TESOL endorsement may teach the English component of the bilingual program.
Conn. Agencies Regs. § 10-145d-475