I still remember my first torrent of second-language swearing. I was 20 and living in an industrial city in northern France and a bloke decided it’d be fine to put his hand up my skirt. I can’t remember exactly what I said, but I do remember being amazed by how much bad language I’d assimilated in a few short months of living in France. Dubbed films and bar conversations had obviously left their mark.
There’s been a lot of research into the effect of swearing in second languages (and the effect of second languages on swearing). Bad language is rarely taught in the classroom, but second language learners, even those who should be “old enough to know better” tend to pick up a smattering of profanity as they approach fluency.
But is swearing in a second language ever as natural as swearing in one’s first? Jean-Marc Dewaele reviewed several studies for his research on swearing in a second language. Years of research have shown that emotional words understood at a deeper level if they are learned in childhood, and that people who speak more than one language will quite often revert to their second language when talking about painful subjects because of the extra distance that this gives them. Taboo words that are heard in your first or dominant language will make your stress levels rise far more reliably than swearwords in a second language – even one that you know very well.
Dewaele carried out a study of over 1,000 people who spoke two or more languages and found that, when it came to automatic swearing in moments of annoyance or frustration, most of them chose to swear in their first language. For example, Sandra, a native German speaker who also could also speak Italian, said, “If I am really angry, only German words come into my mind.” Erica, a native Spanish speaker who could also speak English, Italian and Portuguese, said “[My partner and I] speak in English and we argue in English because he doesn’t speak Spanish. However, many times I find myself swearing at him in Spanish.”
The greater emotional force of swearing in your native language can cut both ways, though. Maria, a native Spanish speaker said “I never swear in Spanish. I simply cannot. The words are too heavy and are truly a taboo for me.” Nicole, whose first language is English, said “My parents were quite strict and I still have the phrase ‘I’ll wash your mouth out with soap and water’ in my head! I’d never swear in English but it’s easier in German!”
Context can be really important too – we experience different types of upset and frustration at different stages in our lives Johanna is a native English speaker living in Italy. She said she was more likely to express Italian in her adopted language. “[S]ince I’ve spent my young adulthood here I’ve gotten more practice raging at the government or the landlord [in Italian]. I still end up feeling ridiculous when I get worked up about things in English.”
Swearing in a second language has its pitfalls, however. things that seem innocuous or even comical in one language can be utterly taboo in another. Sandra, a German and Italian speaker who responded to Dewaele’s study pointed out that “[s]wearing in Italian means talking about God, Maria etc. in an obscene way, which in German doesn’t mean a thing… In German you might use animal names to insult someone but in German it wouldn’t mean anything.” Dewaele also gives the example of an exchange of insults between Iraqi and Kuwaiti officials in 2003 that focused on the state of each other’s moustaches.
Because swearing is so emotionally loaded, we tend to internalise the rules early on in life. Even a fluent speaker of a second language is likely to make mistakes about the nuances and emotional force of bad language words if they learn that language in adulthood. While it might be tempting to try out taboo vocabulary in your new tongue, beware: you might end up being told to get lost in translation.
Dewaele, J. (2007). Blistering barnacles! What language do multilinguals Swear in?! Sociolinguistic Studies, 5 (1) DOI: 10.1558/sols.v5i1.83
thatseffingamazing 
Like the slightly far fetched story of finding out deep undercover agents by knocking them up and then seeing which language they swear in while giving birth?
Hah! Given that it’s the undercover agents knocking people up, this could all get very… reproductive!
I think it comes down to who you are swearing for. If you are swearing at someone and want to get across to them how angry/unhappy you are then I couldn’t see any point in swearing in your mother tongue. You want them to understand how you feel, so you would swear in their language. If you are swearing at yourself because you drop something or hurt yourself then you might do it in your mother tongue.
It also depends on how fluent you are in the second/third/fourth language. I remember when I went to live in Paris, it took a long time to be fully fluent, your brain has to make the move from translating to immediately understanding. You know when you are fully immersed in the language when you think and dream in it. I remember before I reached that stage, I was having an argument with my then boyfriend in French. As I got more upset I could only swear at him in English. However, he also spoke very good English, so I knew he got the meaning! When I lived in Germany I would get quite bad road rage during the commute and would often shout “Wichser!” (wanker) at nobody in particular from behind the wheel when I got cut up. Although, this may also be because the German word has a harsher sound to it, so I prefer it :) When I hurt myself I was surprised that in France and Germany I said “aïe” and “aua” instead of ouch. My mother tongue didn’t take over in those instances.
The brain works in mysterious ways: the other morning I was on the tram and as it pulled away I fell into another lady. My immediate reaction was to say “pardon”, but not in a French accent. Afterwards, I thought to myself “What language was that? Why did I say that?” and when I got to my Czech lesson I told my teacher and she said that was the correct word in Czech for sorry in that situation. So, even as a beginner in Czech, somehow my brain had stored this word and brought it out at the right moment.