About what you put in the log message: You can also put different fields in a line of text. Not getting the advantage or trade-off here.
About the internationalisations: As non-English developers we force all our systems who have logging internationalisation to English system language so we have a common ground for the messages. Understanding the English message is nearly no burden. Log Messages are Event triggers, either in code or in a developer's/admin's mind. If I get a log message in my native language I don't know which event that triggers, which makes it actually harder.
Really. I don't know any non-English person who considers log internationalisation a good thing. Fighting anglocentricism is a very anglocentric topic. Outside of UK/US that's a non topic. We (non-English people) are happy that there is a language we can use to talk to each other and we don't really care how it came to be that widely known.
And even if you don't speak English, I don't see the advantage of parsing \x03 instead of "Error:.*". Both are strings that have a meaning which is rather independent of its encoding.
