Every manual to learn the Thai language, with English, Dutch or any other Western language as a base, is strugling with the problem of the conversion of the thai characters to the own (Latin) script.
The use of English with its inconsistent pronunciation only makes it worse. Moreover many Thai loanwords exist from Sanskrit and Pali and upon these often other rules are applicated than for Thai. Consider how an Englishman could pronounce the word Pali...
The Thai standardisation (RTGS) is not consistent but nevertheless it seems to be a more or less useable starting point. On this site preference is rather given to the Pali denomination for the festival days than to the Thai standard or any of the many other ways of writing that we encounter. No diacrititic symbols are used:
