It is no secret that code-switching between languages is a specialized skill which places a burden on one’s brain, since it is never easy switching between two or more language systems, especially when they are quite different and operate on different types of grammatical logic. There is evidence that in multilingual societies code-switching between commonly used language varieties is automatic and that multilingual speakers are trained since birth to communicate in more than one language, which comes as second nature to them. Speaking from personal experience, growing up in Hong Kong we certainly had to counter-balance Cantonese (vernacular) and Mandarin (formal literary) in our day-to-day usage (English too as HK used to be a British colony), which gave rise to native multilingual proficiencies among the educated masses. When I became an interpreter, I started using some more exotic combinations, though mainly centred around English since I was working for clients in England and the US, so I was regularly asked to do Spanish-English and Chinese-English both ways. I certainly did find it difficult going from one language to another, since these languages were really quite different (especially Chinese-English) and I always had to think very deeply and carefully so as not to make grammatical mistakes in my translations. There was one particular occasion though which gave me probably the hardest type of code-switching I have ever done. At my first ever LSA Institute in 2011, I was fortunate to be in the company of my fellow linguists, and there we exchanged many amazing linguistic encounters, especially during our evening pub crawls after long days of linguistic seminars and lectures. I remember one occasion where I was seated between a native Spanish speaker and a Japanese coursemate and I ended up code-switching between Japanese and Spanish as I alternated conversations with them. That was a totally new experience for me since I had never code-switched between these two languages before and I dare say that it gave my brain a lot of exercise. I suddenly had to move from head-initial Romance structures to head-final Japanese constructions, not to mention the many phonemic differences and completely different vocabulary which made it quite a roller-coaster for my linguistic brain. I remember at the end of it feeling so exhausted from having to think that hard about different grammars (and grammatical analysis was and still is what I do for a living) that I had a huge headache and had to go to bed immediately. It was quite a strange experience, though utterly exhilarating as it gave my brain some very healthy cognitive exercise. In my day-to-day life I regularly have to code-switch between different languages, but doing it within really unusual language combinations (like Spanish-Japanese) rarely happens. Wonder when/where I can do that again as my brain is just itching for some new exercise. Don’t scientists say that multilinguals have healthier brains than monolinguals? If so, I expect to live to a hundred!