Чем плохо "Мой брат думает за себя"? Таки грамматически правильно. И по значению подходит.
В русском языке есть выражение "Думай за себя". И его употребляют именно носители...
«Думать за себя» употребляется в другом значении, и часто в сочетании «каждый думает (сам) за себя». В значении «думать самостоятельно» так сказать нельзя.
А в чём Вы видите принципиальную разницу между - Думать за себя и Думать самостоятельно. И в том и в другом случае, имеется в виду "принятие решения".
Возможно - "думать за кого-то" имеет легкую негативную окраску, но смысл-то остается.
If you say "My brother is thinking by himself.", that wouldn't really express autonomy (not like "for himself"). It would express him being the only one thinking at his location. It would be similar (but not the same) as "My brother is by himself, thinking."
Like, taking the point and making your conclusions but without saying them out loud?
Yes. As in, contemplation. As compared to "for himself", which means he is independent and doesn't need help.
In comparison to all of these, what exactly does "сам" suggest in this sentence?
"To think to oneself" is a set expression, both in Russian and in English. In Russian it would be думать про себя or, indeed, just "думать". After all, you rarely say "SOMEBODY though to himself, full stop". Normally you add what it is they thought to themselves. And in such situation you may choose to fall back to just "think" because this is an action that is automaticlly presumed to be happening only in one's head.
сам suggests what it says on the tin: the person thinks on his own, without using people's help or their insistent and maybe annoying advice. Or, well, he might behefit from their advice but prefers to do his own thinking first. That's what сам essentially means: performing action on one's own, yourself. Depending on the context, English might express it as "on one's own", "oneself", "by oneself" and even "for oneself" (=trying something out to see if it is as people say).
Shady, Я не очень понимаю разницу между "думать про себя" и "думать о себе," to think about oneself. Isn't "про себя," --"about oneself"?? На пример, нельзя сказать, "Я всё рассказал про себя."? (I said everything ABOUT MYSELF.[?])
It may mean both. However, it does not make much sense to interpret Сергей подумал про себя «Что за день!» in English as "Sergey though about himself "What a day!"
Кстати, по поводу последнего замечания. Так сказать можно. Предлоги ПРО и О синонимичны, хотя и несколько отличаются коннотациями.
Предлог О (об, обо) на порядок популярнее "про".
Ну и голос у этого бота, ребятки. Не понятно даже носителю русского языка :(
Точно подмечено )) Added an alternative pronunciation here: https://forvo.com/phrase/%D0%BC%D0%BE%D0%B9_%D0%B1%D1%80%D0%B0%D1%82_%D0%B4%D1%83%D0%BC%D0%B0%D0%B5%D1%82_%D1%81%D0%B0%D0%BC/
Here is a sentence that demonstrates the difference between "think" and "believe" in English. "My brother believes for himself." doesn't work. But "I think the children want water." and "I believe the children want water." are the same thing. Do you mean to tell me that I think the children want water, but don't believe it? I think not!
I put "my brother is thinking about himself". As in he needed to make a decision and the choice he made benefits him more than the other choices. Could this sentence be used like this? If not, how would you say it?
It could not, which hardly comes as any surprise. You can say "Он думает о себе"
In my opinion no - because it doesn't stress enough that he thinks independently. You may be thinking alone after someone just briefed you on the subject you are now thinking about alone
"Мои брат думает сам" That's what I wrote and it marked it wrong. didn't say I missed an accent or spelled anything wrong... error?
Right, but usually it won't mark it wrong, it'll just tell me I got an accent wrong but still give me credit. In this case it wanted perfection I guess.
Й and И are two separate letters in the Russian alphabet. It's not an accent mark. And the meanings are different. Мой брат is my one brother. Мои братья are my brothers (plural). The possessive pronoun has to match the singular or plural noun that they modify. You used the plural "my[мои]" for a singular noun "брат." Мой is the singular.
There's a little bug in here. Pressing the loudspeaker button the sentence starts with мой, but pressing the turtle button you can hear it start with них. This induces in error.
Not really. "Sam" is usually transliterated as "Сэм". Besides, using a noun in place of "сам" wouldn't make grammatical sence for this sentence.