The official language of Thailand is Thai. Like Mandarin and Vietnamese, Thai is a tonal language (think of the difference in your voice when you say “yes” as opposed to “yes? ), which can make it difficult to learn non-tonal languages quickly, but even so, everyone will appreciate your efforts, so pick up a phrasebook and give it a try. Thai is a language with many dialects, although the Bangkok dialect, also known as Central Thai, is used as the standard and taught in all schools. There are language schools in all major Thai cities, including Bangkok and Phuket.
In the Muslim-majority south, dialects of Malay are spoken that are largely unintelligible to speakers of Standard Malay/Indonesian. Various Chinese dialects are spoken by the Chinese ethnic community, with Teochew being the dominant dialect in Bangkok’s Chinatown and Cantonese speakers also forming a significant minority within the Chinese community. In the south, in Hat Yai, Hokkien is also well understood due to the many tourists from Penang. The eastern Isaan dialects are closely related to Lao, and in the northern tribal areas there are dozens of small language groups, some of which are so remote that there are few Thai speakers.
Public signage is usually bilingual, in Thai and English. There is also some dominance of Japanese and Chinese signs. Where English is used, it is generally quite phonetic – for example, “Sawatdee” (meaning “hello”) is pronounced exactly as it reads: sa-wat-dee. There is no universal agreement on how to transcribe Thai letters that have no equivalent in English. For example, Khao San Road is also spelled Kao Sarn, Kao Sahn, Khao San, Koh Saan, Khaosan and many other variations. Maps with names in Thai and English make it easier for locals to help you.
Most young Thais learn English at school, so many young people have a basic knowledge of English, although few are fluent. Most receptionists in the travel industry speak at least enough English to communicate, and many are relatively fluent; some also speak one or more other languages popular with their clients, such as Chinese, Japanese, German, etc.
Many Thais have difficulty pronouncing English consonant groups. The common confusion is that Thais often pronounce “twenty” as “TEH-wen-ty” so that it sounds as if they are saying “seventy”. It is therefore advisable to use the calculators that street vendors offer you to avoid confusion about the prices offered when buying goods.