Lao language
Thai is written in the Thai script, an abugida written from left to right. Many scholars believe that it is derived from the Khmer script. Certainly the numbers were lifted directly from Khmer. The language and its script are closely related to the Lao language and script. Most literate Lao are able to read and understand Thai, as more than half of the Thai vocabulary, grammar, intonation, vowels and so forth are common with the Lao language.