Indigenous Languages Development Act Article 14

Official documents of governmentagencies, schools and public enterprisesin indigenous regions shall be writtenin regional languages.
中文原文 原住民族語言發展法第14條
原住民族地區之政府機關(構)、學校及公營事業機構,得以地方通行語書寫公文書。

English translation for reference only; the Chinese text prevails. Not legal advice.