Your problem is the problem of all non-native English speaking people.
It is hard not to think in your language and then translate it into English. And, unless you live in an English speaking country (where your only chance is to speak in English all the time), this will be your (our) problem all the time.
I am a translator, mainly translating medical articles. Thinking in Turkish (my language) and then translating it into English is not a problem in medical area. Because medical vocabulary is more Latin than English or any other language. So I'm fine there.
But I'm somehow used to think in English. Especially when I try to remember the meaning of a word in English, I tend to ask the question in English in my mind. But that is not the case for most of the other topics.
And there's the emphasis issue. Non-native speakers of any languages would place the emphasis on the wrong words most of the time, no matter how experienced they are.
I can guarantee that any article written by me will be understood better by a Turkish person regardless of the quality of the usage of English in the text. So, zero mistakes in English doesn't mean that everybody will understand what you meant.
This is why most of the questions have long explanations, or subsequent questions. I am thinking that I asked just what is on my mind, but another person gets it in a whole different way.
So, that would be F for me. I don't care. Probably as a non-native English speaker, I understand what you say better than the native English speakers
About google translation, it depends on the language pairs. If sentence structures are similar between the languages, then it does a good job, but if the sentence structure is different, Google Translation is worse than your own words. I reject proofreading projects as soon as I realize that it is a machine translation
Anyway, this problem would have less importance if we could set our primary language in our profiles. It won't make it go away, but it would make it easier.