Taivoan language influenced by Siraya
Criticism against Candidius' famous assertion
Taivoan was considered by some scholars as a dialectal subgroup of the Siraya ever since George Candidius included "Tefurang" in the eight Siraya villages which he claimed all had "the same manners, customs and religion, and speak the same language." However,  American linguist Raleigh Ferrell reexaminates the Dutch materials and says "it appear that the Tevorangians were a distinct ethnolinguistic group, differing markedly in both language and culture from the Siraya." Ferrell mentions that, given that Candidius asserted that he was well familiar with the eight supposed Siraya villages including Tevorang, it's extremely doubtful that he ever actually visited the latter: "it is almost certain, in any case, that he had not visited Tevorang when he wrote his famous account in 1628. The first Dutch visit to Tevorang appears to have been in January 1636 [...]"Lee (2015) regards that, when Siraya was a lingua franca among at least eight indigenous communities in southwestern Taiwan plain, Taivoan people from Tevorangh, who has been proved to have their own language in "De Dagregisters van het Kasteel Zeelandia", might still need the translation service from Wanli, a neighbor community that shared common hunting field and also a militarily alliance with Tevorangh.Li noted in his "The Lingue Franche in Taiwan" that, Siraya exerted its influence over neighbouring languages in the southwestern plains in Taiwan, including Taivoan to the east and Makatao to the South in the 17th century, and became lingua franca in the whole area.