Should have known Taiga from Magic: The Gathering. Oh well. Also, the Gulf of Tonkin incident wasn't a fake incident... there really was an incident... but the events of that incident were obfuscated and misrepresented to help make a case for war.
“One of the official languages of South India, Sri Lanka and Singapore” could have been a more accurate hint rather than “Language of southern India and Sri Lanka”. South India comprises of five different states with four distinct official languages. Otherwise, a very interesting series of quiz!
Tamil originates in South India, and in my opinion, the hint is not at all wrong. India, meanwhile, has only 2 official languages — Hindi and English. Tamil is actually a Scheduled Language and hence recognized in India.
Also, I agree with you. Great quiz series!