Talking about how to say "Thailand" correctly is nothing new. From time to time, we heard people pronounce "Thigh-land." How can you blame them? It starts with "th" right?
Thailand was previously known as "Siam." Remember the movie "The King and I"? In the film, King Mongkut was known as the King of Siam!
ํYou may have heard the word like "Siamese Twins", which is used for the conjoined twins, and "Siamese cat", the breed of cat with a unique color. That's right. The original Siamese twins and the Siamese cat were from Thailand.
Thai people, in general, have a hard time pronouncing "th" sound. It's likely that when the leaders of Thailand changed the country's name from Siam to Thailand in 1939, they were not concerned about the different pronunciation between "th" and "t". We really don't know why they chose to spell Thailand, not Tailand.
By the way, Thai people are not from Taiwan. Taiwan people are called Taiwanese. Thailand and Taiwan are two different countries. :-)
If you ask any Thai people, you'll be surprised that American people often mistake us as citizens from Taiwan. We are from Thailand, not Taiwan! You see, it's somewhat confusing. Both countries sound similar.
No wonder, sometimes people called Thailand as "Thigh-Land". It's phonetically correct, though! :-)