language, truth, lies, speech bubbles

Truth or lies: Why it is harder to know when spoken in a foreign language

There has been a lot of research lately on how speaking a different language can alter an individual’s personality. In fact, eSense Translations wrote an article on the subject last year.

More recently, studies have looked at how speaking a second language affects your ability to lie. At eSense Translations, our blog this week takes a closer look at this question and reviews the reasons behind why speaking a different language may have this effect.


There are two opposing theories on how speaking a foreign language may affect the ability a person has to tell untruths.

The first one is that speaking a second, non-native language hampers the ability to tell lies because of the additional cognitive demand it places on the individual. In other words, as speaking in a foreign language is obviously more difficult than communicating in one’s native language, it takes longer to formulate the words to create a believable lie. Hesitation may occur, as one tries to find the most appropriate vocabulary to be convincing.

The second opposing theory suggests that it is actually easier to lie in a second language, as there is less emotional connection with what you are saying. Telling lies in your native language is thought to evoke past experiences and thus make you uneasy about doing so. Our early childhood experiences contribute to our brain development and the way in which we use language. For example, you may have been brought up with your parents and teachers advising you that telling lies is a bad thing to do, so when you do utter an untruth, you feel guilty about it. It is thought that the connections to these feelings and past experiences are stronger when you are attempting to tell lies in your own language.


A study completed in May 2018, published in the Journal of Experimental Psychology, looked to provide evidence to support one of these theories. Participants in the study responded to a range of emotional and neutral questions in either English (their native language) or German (a foreign language). When answering they were provided with a cue, which told them to either tell the truth or lie.

Results showed that there was a smaller difference in response time between telling the truth and lying when speaking in German (their foreign language) than when speaking in their native tongue, English. This meant that it was harder to tell if the person was lying when they spoke in a foreign language.

The reason behind this difference was actually due to a longer response time when telling the truth in a foreign language, so although we may hesitate when telling a lie in a foreign language, this hesitation also occurs when telling the truth and therefore the difference is less notable to the recipient.

When speaking in one’s native language, the difference between telling the truth and telling lies is more marked.


This study was only small in scale and more evidence is needed before any definite conclusions can be drawn and we can have a more certain idea on how the language we speak affect what we say. Nonetheless, it does give us an indication that deciphering when people are lying is more difficult when they are not speaking their own native language.


This study may be of interest to recreational language learners, but as more evidence is gathered and more certain conclusions can be drawn, this type of research could prove to be particularly useful for work in the legal and immigration system, for social work where language is a factor and also to businesses, who do their market research in a variety of locations across the world.

The area of study is also of interest to us at eSense Translations, as the conclusions drawn could then have an impact on how interpreters are used in the future. We will continue to review this area of research and keep you updated with any information we discover.


By Lorna Paice


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