 Delta – Diploma in Teaching English to Speakers of Other Languages Delta is an internationally recognized professional teaching qualification that is designed for teachers with some experience in the classroom. The certificate is widely considered to be a follow-up to the SELTA certificate and is often taken by teachers in order to update and improve their existing English language teaching skills. The course is considerably more in-depth than the SELTA certificate and is assessed through a combination of examinations, coursework, and in-class assessment. The Delta course is split into three sections which can be taken individually or at the same time. An individual certificate is awarded on completion of each module, while the main certification is presented upon completion of all three sections. As with the SELTA course, this certificate is awarded by Cambridge ESOL.