Practical driving test in English

In my previous experiences, some traffic instructors suddenly become rude or stop smiling like when they greet you for the first time and you say you are not good in swedish and if they could switch to english.
Noticed that their attitude changes suddenly and they get quite uncomfortable making the student uncomfortable. At least this was my experience after 3 failures. Not all are like this but I had 2 out of 3 like this. This stressed me more and I failed.