But they’re definitely T’s in the alphabet. I know this because I was told by Tongans on my mission that the hard T sounds funny to their ears (almost feminine).
But yes, there are T’s in Tongan. As someone else pointed out though, you will never see a g without an n in front of it. N and Ng are separate letters in Tongan alphabet. So a lone g is a dead giveaway that it’s Samoan.