I found this post from one other applicant who had the application returned because it wasn't translated (even though the document was both in English and Tamil) https://www.canadavisa.com/canada-immigration-discussion-board/threads/june-2018-citizenship-applicant.573556/post-7111707
Looks like he resubmitted with a translated version of the birth certificate and got his citizenship.
Looks like he resubmitted with a translated version of the birth certificate and got his citizenship.