There are four major dialects of Thai: Northern (Kam Mueng, Yuan), Northeastern (Isan, Lao), Central (Siamese), and Southern (Pak Tai). Standard Thai, the official language of instruction, is based on a prestigious social class dialect of Siamese. In addition to Thai, a great number of other languages are spoken by indigenous peoples, of whom some individuals are literate in thrir native languages. Foreign languages used in Thailand consist of classical (Pali, Sanskrit, Arabic) and modern (English, Chinese, French, Japanese, German, Spanish, Italian, Russian, Arabic). English is the most widely used foreign language.