How to chang lanaguage on Youtube page

I see  some  youtube  page is on Thai  but  some is on English .It make me doubt ? How can i change  this language on Youtube …

It ‘s not long time ..I can fix this trouble …This is way to change  language on Youtube  page .It is very simply .On youtube page  .Look at the bottom  and move the cursor to the end of the web page. A menu to change Just click to change it  to the language  as you want .