Have you ever felt that people change vocal timbre and tone when changing language? If you are like me, you have also gotten sometimes annoyed because people seem to get warmer when changing to their native language or logical and assertive when speaking in their second language. After listening to the course Language and the Mind (chapter 23 on bilingualism) I learned that similar phenomena have been documented by several noted researchers and used as useful tools to further explore the intimate link between language and the mind.

The audiobook itself is full of intriguing ideas. Being a course it is quite difficult to follow and remember all the arguments without serious revisions and careful reading of extra materials after each session (chapter). Nevertheless, it could be a good compendium from which one can get an overall feeling about the subject and a starting point for more research into particularly catching concepts.

The author does a good job of presenting the different arguments and interpretations when there is no consensus in the community. The teacher, Spencer Kelly, is a professor of psychology and neurosciences, and he offers a scientific approach always citing scientific studies. Most of the time though it is difficult to estimate the strength of different arguments. For example, my feeling is that most studies in the field are plagued by methodological flaws and reproducibility failures. Therefore, it is important to know for each study of interest its statistical power. More importantly, has anyone tried to replicate it and/or has the replication has been successful?

About bilingualism, I have always assumed that emotion is quite difficult to express in a second language, and it comes easier in the native language. Also, intelligent and proficient speakers of a second language make painstaking efforts to mimic native speakers and use the correct grammar, vocabulary and intonations. This would explain my observations, but many studies, as those by Boaz Keysar and Albert Costa , cited in the course, suggest that bilingualism can transform the brain. Ethics, logics and emotion can be markedly different in a second language. I was definitely wrong being annoyed.