According to legend, King Ramkhamhaeng, The youngest son of King Si Inthratit, the first king of Thailand, modified the Sinhala (Sri Lankan) Script to create the Thai alphabet. The first written Thai language is inscribed on a stone known to Thais as the "Ramkhamhaeng stele". However, The Thai alphabet doesn’t look like the Sinhala alphabet. Thai alphabet looks more like the Khmer (Cambodian) alphabet. Thai was once a part of the Khmer empire during King Ramkhamhaeng’s time. Was the Thai alphabet derived from the Khmer or Sinhala alphabet?

To someone who is Thai, does Khmer sound similar to the Thai language?

To someone who is Cambodian, does Thai sound similar to the Khmer language?

To someone who is neither, can you tell the difference between these two languages?

Please share your thoughts, and what you noticed about similarities and differences. Thank you.
So what language do you find more intriguing?

I feel shamed to ask "Do you know Thailand ?" I am Thai. I found that Vietnamese and Indonesia language are available in Google translation machine but Thai. I think in South East Asia several countries such as Laos Cambodia Singapore Myanmar Vietnam Malaysia and China support studying Thai language. However, There are not much programs to promote study Thai or other applications for instance translation, dictionary, reading machine or OCR.
When I register the websites, they want me to inform the language but there is no Thai provided. What happened? Maybe my language is a minority of world language use.