@skinnylatte
While there may not be much written literature in Teochew, there was plenty of written Hokkien, an adjacent language to Teochew, in the form of Pe̍h-ōe-jī (白話字).
@revndm
You might find it particularly interesting, since Pe̍h-ōe-jī was developed by Western missionaries in the 19th century to promote literacy in Southeast Asia. Taiwan's first newspaper, "Tâi-oân-hú-siâⁿ Kàu-hōe-pò" (Taiwan Prefecture City Church News), was published in Pe̍h-ōe-jī.