The history of the translation of the Bible into northern Thai (กำเมือง) in the missionary era is a fascinating story that has received too little attention (Everything about the study of Thai church history has received too little attention!) The job was never finished, and for the most part surviving copies of the northern Thai Bible are contained in scripture portions. One of the best examples is the translation of the Psalms done by the Rev. Jonathan Wilson with Nan Poen, which was published in 1894. The reason I mention it here is because a copy can be found online at the Open Library (here). I came across it quite by accident, and a half hour spent googling different combinations of northern Thai/Lao/Siam Bible produced no other hits (not even this one!).