Google products often choose Thai interface for me and this is the real problem

Can I call it a "bug"?  This is far too annoying.  Yes, I am THAI and my English is not that good BUT the Thai interface SUCKS.  I should have right to choose which Language I prefer.  There is no obvious place where I can set it.  Some products have, some don't.

Fortunately, people find a way to change the interface language by appending these 2 HTTP GET variables depending on the URL you are seeing:

&hl=en
?hl=en

Note that it will only work with your current session.  If you come back later, you may need to do it again.  You should have a real fix for this, Google.