English is a core compulsory subject in Thai schools.  And has been since 1999.  But you'd never know it by talking to a Thai student of any age, whether they are six or 16. Thais spend 12 years at school, 6 years at Prathom level from Prathom 1 - 6, and then 6 years at Mattayom level, from Mattayom 1 - 6.  The first 9 years are compulsory, after which time some students, mainly in the rural areas, may drop out.  English is taught from their first year of school as one of the four core compulsory subjects. 

Thai English teachers have themselves gone through an educational system in which English was not taught.  As a consequence many of them struggle with English themselves, as ironic as that might sound.

It also means that English teaching here relies more on textbooks and the practise of rote memorization rather than on the skills of teachers.  A candid expression of the view of the Thai government towards English skills is contained in a presentatin to UNESCO a few years ago:  http://www.worldedreform.com/pub/paperie13dec07.pdf.    So English is taught as a body of information such as geography or history.  It is not taught as a skill.  So to use an analogy:  students know a lot about bicycles.  But they can't ride them.

Many students go through the entire system and graduate from university with English conversational ability that is nearly non-existent.  Too much time is spent on reading, writing and grammar and not enough time on speaking and actually creating language for themselves. 

Conversational skills are weak.  But what students do have is a very broad knowledge of English words.

We see this as the key for our volunteers.  Helping students use their vocabulary skills to develop conversational skills requires a very specific strategy and effective lesson plans.   We provide both to our volunteers. So at the end of even a very short placement, teachers observe very real changes in their students' ability.