No one can deny the fact that language changes and shifts. Many cases have been detected; for example, a Tai Yuan or Khammueang dialect spoken in Maecaem district, Chiang Mai has Lua' lla'vuua?/ or a Mon-Khmer substratum in its pronunciation due to language shift. The peculiar Maecaem accent is caused by unusual phonation types which are common in Mon-Khmer languages.