High Quality Content by WIKIPEDIA articles! Ysgol Dyffryn Teifi is a bilingual (Welsh and English) comprehensive school in Llandysul, Ceredigion. It stands on the site of the previous Llandysul Grammar School. The school was established in 1984 following the re-organisation of education in the Teifi Valley. The school`s history dates back to its period as a grammar school in the 19th century.