You will wonder, but not only Latvians are making mistakes in English. I would say, if you meet Chinese or Asian people on board, most likely they will leave typos or make mistakes.
The question here is, does it really matter, and if so, then where exactly and what for does it matter? People can find the common language without paying attention to mistakes. The most important is to understand each other.
Your question sounds like you would be from the Latvian government carrying about the crystal clear Latvian language. They oppose that each Latvian citizen should write Latvian without grammatical mistakes. But this is dumb. Even in their native language, people often do mistakes. This is actually what destroyed Latvia from the inside.
Don't pay too much of attention to the mistakes regular people are doing. We all do mistakes.
So answering your question - I don't understand it. There are most of people which know English perfectly. Like me, he-he

And there are people who doesn't know it at all, but would like to speak it and write it.
How the
trend may be involved in that?..