This english proficiency requirement is an odd one. Take for example UK JAA PP and a Thai PPL licence.
- In Thailand: you need an English proficiency evaluation to fly outside Thailand on a HS-registered plane. You do not need one if you fly within Thai airspace on such a licence.
- UK licence: it states that the language proficiency is English. (Obviously so I would say as all the training and tests/exams are in English anyway). But does such a licence holder need an extra exam to fly outside UK's airspace, like in Thailand?