Even in the Philippines they use Ladyboy so it's not restricted to Thais, maybe they were the first to come up with the word. But regardless of how many names people come up with, their still transsexuals regardless. Kathoey, Newhalf, Ladyboy, etc I believe India have one to but I forget what their called.
Yeah, well either way it's all the same to me. lol people want to confuse to damn much. Because even Japan have one "Newhalf" lol too much bullshit when their all the same damn people. Transgenders.
Actually the term "ladyboy" originally refered only to the Thai third gender or Kathoey, specifically to those that were sex workers. It was meant to facilitate the comunication when the sex trade became more and more international...with time it became almost a similar to shemale or tranny worldwide, but the Thai Kathoey still very much consider it something that belongs, in a way, to their shared cultural heritage.