Go to any Thai concert, they are all singing each others songs and have taken well known foreign tunes and added their own words, and they have been doing this for over 50 years, with western and Indian songs.
One of the most famous songs Thais nicked, from a 1967 film they put their own words to it about a girl from Loei and it featured in the 1970 film monrak luktung. Heard it sung at a concert last week
Another famous tune used, heard this one last week as well!