Consonants

There are 44 consonants representing 21 distinct consonant sounds. Duplicate consonants represent different Sanskrit and Pali consonants pronounced identically in Thai. Their continued use is necessary to differentiate among unrelated loan-words which are Thai homophones. The consonants are divided into three classes - low, middle and high - which determine the tone of the following vowel. There are in addition four consonant-vowel combination characters not included in the tally of 44.

To aid learning, each consonant is traditionally associated with a Thai word that either starts with the same sound, or features it prominently. For example, the name of the letter ข is kho khai (ข ไข่), in which kho is the sound it represents, and khai (ไข่) is a word which starts with the same sound and means "egg".

Two of the consonants (kho khuat and kho khon) aren't used in written Thai anymore. Some say that when the first Thai typewriter was developed by Edwin Hunter McFarland in 1892, there was simply no space for all characters, thus two had to be left out.

Equivalents for Romanization are shown in the table below. Many consonants are pronounced differently at the beginning and at the end of a syllable. The entries in columns initial and final indicate the pronunciation for that consonant in the corresponding positions in a syllable. Where the entry is "-", the consonant may not be used to close a syllable. Where a combination of consonants ends a written syllable, only the first is pronounced; possible closing consonant sounds are limited to 'k', 'm', 'n', 'ng', 'p' and 't'.

Although an official standard for Romanisation is defined by the Royal Thai Institute, many publications use different Romanisation systems. In daily practice, a bewildering variety of Romanisations are used, making it difficult to know how to pronounce a word, or to judge if two words (e.g. on a map and a street sign) are actually the same. For more precise information, an equivalent from the International Phonetic Alphabet (IPA) is given as well.

Each consonant is assigned to a "class" (Low, Middle, High), which plays a role in determining the tone with which the syllable is pronounced.

• Consonant-vowel combination characters, not members of any group.

• • อ is a special case in that at the beginning of a word it is used as a silent initial for syllables that start with a vowel (all vowels are written relative to a consonant — see below).