One adds special markings to the main sign that makes the syllables have a different vowel and becomes an alphabet.
Thai writing system is based on Brahmi script developed to write Siamese or Thai language. Thai script invention was attributed to King Ramkhamhaeng during his reign. Khmer had the possibility of influencing Thai alphabet. The oldest Thai writing dates from 1283. The pronunciation of letters in Thai script is restricted with complex rules where most letters represent similar sounds. The fact was that many sounds established in Indian languages were not categorized in the Thai language; therefore, the same letters came to represent similar sounds in Thai (Suthiwan 23). The phonological changes have made Thai language to combine different sounds into a single sound. The sounds of various Thai letters vary depending on where the letters occurs either on the start or the end of a syllable. The syllable can be ended by six consonants, including /k/, /m/, /p/, /t/, /ng/, and /n/.
In Thai alphabet, the beginning of a syllable is represented by letter C- while at the end of the syllable represented by letter –C. In Thai language there are blue letters including L, H and M, below every phonetic value of the letters. The blue letters denote the class in which letters belong. Another feature of the Thai alphabet is that every letter is categorized into one of the classes including high, middle and low (Suthiwan 37). When the letter appears at the start of a consonant or the syllable ending, the inherent vowel is always left unpronounced. Extra marks and strokes are added around the essential letter in order to create a different vowel rather than the inherent.
Loan words from Pali and Sanskrit are also examples of vowel markers and Thai letters. Thai is categorized as a tonal language such that the pitch is the important to the proper pronunciation of a syllable and how it sounds. There are five different tones in Thai including