Generally the signature of Thai people are not really in any language. Let me explain.
Prior to 1943, Thai names were generally what we call nicknames today. Examples would be Min for a guy and Chompoo for a female. In 1943 the Thai National ID was created. First names and family names now became mandatory for the Thai ID. The next part is kind of like “What came first, chicken or egg?” In a simplistic way, English names and Thai language equivalents are phonetic representations of each other. At this point, you have probably concluded that Thai people were never taught cursive writing which would be correct. As a result, signatures are often a creation of the individual and not really representative of the letters in either language. If you are really curious, the Thai letter versions of the finance ministers and BOT heads are on Wikipedia I believe. As far as translations of the signatures, lol!!!!