I mostly think in English, my first language; however sometimes certain phrases come more easily in French, and then it can be a devil of a time figuring out how to say them in English.
Speaker of 13 languages (to different degrees of fluency) here, and extremely verbal when it comes to “inner thought world” (to coin a turn of phrase).
In my personal experience, it completely depends on context. If I have been “primed” by, for instance, holding a conversation with someone in a certain language, I will keep thinking to myself in that language (of course, during the conversation, I think in whichever language(s) is/are being used).
Regarding dreams, although I rarely remember my dreams, I have found that the language I dream in tends to reflect the one I have been using the most during the day.
I have caught myself thinking in more than one language at the same time, anyway 
Just my 2 eurocent!
Nowhere near fluent, but I was in a situation where I did not speak English regularly for two years.
In my experience, it depended on context. The local language (Fulfulde) was what I used for thoughts like “I’m hungry” or “I am going to the market,” probably because those are the kinds of things I said often in Fulfulde. French was used when thinking about work. I also had a very frustrating habit of re-writing my past encounters…even stuff from high school- into French. I’d find myself walking down the street, thinking about what words I must have used when I argued with my mom about a skimpy shirt, when a moments thought would show that that was in English.
But if I was thinking more complex things, it was in English.
Between my native English and the Portuguese that is spoken in my home, whichever one is the shortest distance from point A to point B.
If there is a particular phrase that fits better, then that language surges forth for the moment, only to be overtaken moments later when a phrase from the other is more suitable elsewhere.
Sometimes it’s just whatever one randomly floats to the top of consciousness. A simple example: yesterday I found myself thinking “Ou caga ou disocupa a privada….” which is how a Brazilian says “Shit or get off the pot.” I then started counting syllables and saw that our version is so much more concise (6 vs 12), but the other is the first one that came to mind regardless.
If I’m practicing a language, I make a conscious effort to think in it. I’m not a visually-minded person, so I more often than not “think in words.” Otherwise, I think in English.
I tend to curse in Russian nowadays, because that’s the one language that no one else I work with speaks. Someone will drop a heavy book on my fingers and I’ll let loose with “Yob t’voyu mat’!!” which loosely translated means “Please watch where you put the book.”
“Watch where you put the book” indeed…
About fifteen years ago one of the Russian chemists at my company taught me several interesting phrases including the one you provided here.
One afternoon I was walking out the front doors and I saw him outside with his back turned to the door, having a smoke. I whispered your phrase to him quietly.
He immediately whirled around with a wild-eyed glare and said “That doesn’t mean ‘have a nice day’ you know!” while wagging his finger.
I laughed and never thought much of it for a decade and a half. Soon after that incident I transferred to a different part of the company.
A few months ago I saw the same chemist walking with another guy and I looked at them and thought to myself… “Wow, I never noticed that that guy’s brother worked here too.” They looked like identical twins, though one was a bit more stooped than the other.
Then I realized: fifteen years ago I accidentally told the guy’s brother, a total stranger to me, to go f*** his mother :eek:. It’s a wonder he didn’t slug me.
I think in whatever language I’ve been using the most recently. I don’t think I dream in words, I can’t think of any instance where I used *any *language in my dreams.
I grew up with both English & Afrikaans, and I think in whichever one I’m currently speaking most of, which nowadays is usually English, since my wife isn’t naturally tweetalig. Although we speak Afrikaans when we don’t want DibblerKid to understand us.
13?!?!
English is my mother tongue, but during the school day, I teach two classes in German. However, when I’m teaching other classes, I find myself sometimes having a “brain fart” as I consciously have to stop and think, “What language am I supposed to be speaking in?” I have found myself dreaming in German, especially if in class we’re working hard on a particular concept in grammar. But then I find myself teaching in my dreams a lot. I know, get a life. :rolleyes:
Yes, 13… (where is the “blushing” smiley when you need it?)
Mother tongue: Spanish.
Fluent to a (hopefully) nearly native degree: English, French, Catalan.
Reasonably good: Russian, Japanese, Dutch, Italian.
Working Knowledge of: German, Romanian, Portuguese.
Basic knowledge of: Arabic, Mandarin Chinese (increasing it now).
At work (I work for the European Patent Office) the official languages are English, French and German, and we are supposed to be able to use all three.
I have some languages “in the pipeline” to learn, after I get better at Arabic and Mandarin Chinese.
Just my 2 eurocent!