Patrick McGuinness in The Guardian:
A third of the way through this absorbing and engagingly written book, Albert Costa describes a family meal: “The father speaks Spanish with his wife and his son, but uses Catalan with his daughter. The daughter in turn speaks Catalan with her father but Spanish with the rest of the family, including the grandmother, who only speaks Spanish though she understands Catalan.” It’s what Costa calls “orderly mixing”, and, depending on which restaurants you visit, a common enough situation: everyone is bilingual here, but the language used changes according to who it is directed at. Given that everyone at the table understands both languages, would it not be easier and less confusing if everyone just chose one language and stuck to it? That sounds logical, but the bilingual mind doesn’t work that way. If you do not believe it, Costa suggests “having a conversation with a friend in the language you do not usually use and see how far you get”.
Not far, he observes. And Costa should know – not just because he was an expert in language acquisition (he died last year), but because the family he is describing is his own. One of the reasons this book makes sense of its complex material – from basic code-switching tests to the latest technology in brain imaging and transcranial magnetic stimulation – is that Costa is such a charming and witty guide. This is a rigorous book about complex science, and much of it could have been intractably technical or riddled with statistics. But Costa has a winningly informal style, a deadpan wit, and mixes laboratory findings of cognitive neuropsychology with examples from everyday life, TV programmes, sports and politics. In one set of cognitive tests, he shows how people are more risk-averse in their second language, and more gung-ho in their first. Costa suggests the practical applicablity of such research by advising us to visit casinos where people speak a language we are less comfortable in – it substantially reduces the likelihood of our going home shirtless and barefoot.