Lao is a Tai language spoken by 7 million people in Laos and 23 million people in northeast Thailand. After the conclusion of the Franco-Siamese War of 1893, the Lao-speaking world was politically split at the Mekong River, with the left bank eventually becoming modern Laos and the right bank the Isan region of Thailand (formerly known as Siam prior to 1932). Isan refers to the local development of the Lao language in Thailand, as it diverged in isolation from Laos. The Isan language is still referred to as Lao by native speakers.
Isan houses the majority of Lao speakers and the affinity of shared culture with Laos is palpable in the food, architecture, music and language of the region. In its purest spoken form, the Isan language is basically the same as Lao spoken in Laos. Using just tone and some lexical items, there are at least twelve distinct speech varieties of Isan, most of which also continue across the Mekong River into Laos. In fact, the different speech varieties on roughly the same latitude tend to have more affinity with each other, despite the international border, than to speech varieties to the north and south. Only a handful of lexical items and grammatical differences exist that differentiate Isan as a whole, mainly as a result of more than a century of political separation between Isan and Laos, but most of these terms were introduced in the 1980s when Isan was better integrated into Thailand's transportation and communication infrastructure.
Comparison of spelling and orthography
Isan and Lao have drifted away from each other mostly in terms of the written language. The Isan people were forced to abandon their traditional Tai Noi script and have come to use the Thai written language, or Isan written in the Thai script, for communication. In Laos, Tai Noi was modified into the modern Lao script, but several spelling changes in the language during the transition from the Lao monarchy to the communist rule moved Thai spelling and Lao spelling of cognate words further apart. Isan, writes all words with Thai cognates as they exist in Thai, with clusters, special letters only found in obscure Sanskrit words and etymological principles that preserve silent letters and numerous exceptions to Thai pronunciation rules although a small handful of Isan words, with no known or very obscure Thai cognates, are spelled more or less the same as they are in Lao.
Lao spelling in Laos was standardized in the opposite direction. Whilst previously written in a mixture of etymological and phonetical spellings, depending on the audience or author, the language underwent several reforms that moved the language towards a purely phonetical spelling. During the restoration of the king of Luang Phrabang as King of Laos under the last years of French rule in Laos, the government standardized the spelling of the Lao language, with movement towards a phonetical spelling with preservation of a semi-etymological spelling for Pali, Sanskrit and French loan words and the addition of archaic letters for words of Pali and Sanskrit origin concerning Indic culture and Buddhism.
Spelling reforms under the communist rule of Laos in 1975 were more radical, with the complete abolition of semi-etymological spelling in favor of phonetical spelling, with the removal of silent letters, removal of special letters for Indic loan words, all vowels being written out implicitly and even the elimination or replacement of the letter ຣ (but usually pronounced /l/) in official publications, although older people and many in the Lao diaspora continue to use some of the older spelling conventions. The examples demonstrate the differences between Lao and Isan, using Thai orthography, but also that between archaic and modern Lao, as well as the general pronunciation and spelling practices between Standard Thai and Standard Lao in general.
Silent letters
Numerous loan words from other languages, particularly Sanskrit and Pali, have numerous silent letters, sometimes even syllables, that are not pronounced in either Thai, Isan or Lao. In most cases, one of the final consonants in a word, or elsewhere in more recent loans from European languages, will have a special mark written over it (Thai ◌์ / Lao ◌໌), known in Isan as karan (การันต์) and Lao as karan/kalan (ກາລັນ/archaic ກາຣັນຕ໌ ).
