#1
Around the world, most people – estimates vary from 60 to 75 per cent – speak at least two languages, suggesting the human brain has evolved to work in multiple tongues.
Multilingualism has been reported to have many social, psychological and lifestyle advantages. And if they're not enough, researchers are finding health benefits from speaking more than one language, with faster stroke recovery and delayed onset of dementia being just a couple of examples.
#2
Also, there are findings that suggest we might think different when we "switch" to another language. In the 1960s, psycholinguistics pioneer Susan Ervin-Tripp asked Japanese–English bilingual women to finish sentences in each language.
She found that the women ended the sentences very differently depending on which language they used. For example, “When my wishes conflict with my family…” was completed in Japanese as “it is a time of great unhappiness”; in English, as “I do what I want”. Another example was “Real friends should…”, which was completed as “help each other” in Japanese and “be frank” in English.
From this, Ervin-Tripp postulated that human thought takes place within language mindsets, and that bilinguals have different mindsets for each language.


