Somebody obviously went native...
Last I checked, you needed three uninterrupted years on the same visa
to begin applying for permanent residence
. Also, you will be given a test of Thai
. For this, you should prepare for their Thai sixth grade exam for foreigners
You can circumvent all these rules legally if you enter Thailand
with 2M Baht
(about US$60K) in your pocket, or have a pension of about a thousand a month. Thais like foreign money. On those terms, they'll let you stay as long as you want.