This chapter provides a broad outline of the key features of the Thai writing system. The Thai alphabet is conventionally described as having 44 consonants, although two of these, kor koo-ut and kor kon, fell out of use more than a century ago. The letters reu and leu are not regarded as consonants, but the letters ror reu-a and lor ling are to be followed respectively in dictionary arrangements. Consonants are arranged according to the order of letters in the traditional Indian alphabet. All consonants are pronounced with an inherent -or vowel sound. Each consonant has a name, rather like 'a-for-apple, b-for-bat', which children learn in school. For the foreign learner, knowing these names can be useful when asking how to spell a word, but it is not necessary for learning to read. Many consonant symbols change their pronunciation at the end of a word.