WE ALL speak the same language, according to the linguist Noam Chomsky. A Martian scientist, he has observed, “might reasonably conclude that there is a single human language, with differences only at the margins”.

To Earthlings, however, such differences often look anything but marginal. For some, they are barriers to be overcome. But for many others, they are borders to control and identities to be kept apart.

Following the UK’s referendum vote to leave the European Union, there were a number of incidents that raised fears about xenophobic hostility. In one, a foreign-born student was stabbed in the neck with a broken bottle after a group of men heard him speaking his native language. “One of them said he had a daughter living round the corner and he didn’t want her to hear us talking Polish,” the victim told The Independent.

Presented with the idea that a man should use potentially lethal force to protect his child from the mere sound of a foreign language, drifting through the air on a warm summer night, the Martian scientist might reasonably decide to look farther afield for intelligent life. Earthling scientists studying languages don’t have that option. They have to create hypotheses and theories from the stuff of hotly disputed beliefs and values. Language research may need to be screened from its implications and the passions they arouse.

Researchers have devised different ways to create firebreaks between values and data. According to anthropologist Chris Knight, Chomsky’s strategy was as radical as his politics – and he developed it in order to enable himself to sustain his left-wing political commitments.

In his new book Decoding Chomsky, Knight (who mounts his own critique from a position on the radical left) argues that Chomsky needed to deny any connection between his science and his politics in order to practise both while based at the Massachusetts Institute of Technology, an institution that was heavily funded by the US military.

“Chomsky needed to deny any connection between his science and his politics in order to practise both“

This required detaching language from society altogether. Chomsky built an idealised model of language, stripped of its social fabric and removed from the hands of the anthropologists who had traditionally provided linguistic data. “If language could be reduced to pure mathematical form – devoid of human significance – its study could be pursued dispassionately,” Knight observes, “as a physicist might study a snowflake or an astronomer some distant star.”

It takes resolve to keep this most human of faculties detached from the shared experience of being human, but Chomsky did not hesitate to deny that the raison d’être of language is social. Language “is not properly regarded as a system of communication”, he declared. “It is a system for expressing thought, something quite different.” In this view of language, other people are peripheral. As far as Chomsky is concerned, says Knight, language “exists for talking to just one person – yourself“. Other workers in the field do not deny the social implications of their studies, but opt to leave them unspoken.

One of the most energetic research programmes in the science of language is investigating the possibility that bilingualism boosts the efficiency of the brain and protects it from deterioration in later life. It developed around the hypothesis that the brain of someone who knows two languages has to choose constantly between them, and that this exercise boosts its powers of control.

More recently, however, the claims of a bilingual cognitive advantage have been challenged, and it has become a conflict zone in the “reproducibility crisis” that has thrown all kinds of psychological findings into question. Now it’s not just the values that are controversial – even the facts are.

The journal Cortex published a series of papers on the row last year. Tellingly, it was the leading sceptics, Kenneth Paap at San Francisco State University, and his colleagues, who made a point of stating their belief “that the advantages of bilingualism across a host of personal, economic, social, and cultural dimensions overwhelmingly preponderate any disadvantages”. In a follow-up article they pointed out, also tellingly, that only one contributor, Virginia Gathercole, at Florida International University, Miami, mentioned the debate’s socio-political overtones.

Their declaration showed that if you want to support bilingualism but don’t consider that your stance has a sound scientific basis, you have no option but to reveal at least a hint of your values in your scientific discourse. It also suggested a reluctance among scientists to admit even a hint of their social context.

Gathercole herself recalled how in the early 20th century, growing nationalism in the US created political pressure against bilingualism – and how researchers added to that pressure with claims that bilingualism caused “mental confusion” among immigrants. One unspoken issue in the current controversy, she observed, is “undoubtedly some concern” that it could reverse the “positive press” bilingualism has enjoyed as a result of the claims of cognitive benefits.

Whatever the researchers’ concerns or intentions, the significance of the “bilingual advantage” idea is that it appears to take bilingualism out of politics. If you propose that a society benefits from having more than one language, you will provoke some resistance, resentment and rage. But if you argue that brains benefit from having more than one language, especially through reduced vulnerability to dementia, nobody could possibly counter that this is undesirable.

Improvements in health and cognitive performance are unarguably good things – and so they are politically significant, despite appearing apolitical. If they become scientifically established, they will offset the arguments of those who object to bilingualism on other grounds.

“In the early 20th century, growing US nationalism created political pressure against bilingualism“

If not… well, as someone who writes about science rather than actually doing it, I’d be disappointed. But I have already taken comfort from the sceptics’ readiness to affirm bilingualism’s advantages in other areas.

Trenchant and compelling as Knight’s critique of Chomsky is, few scientists would follow him all the way to his concluding vision of science united with revolutionary politics. But maybe it wouldn’t hurt for researchers to hint at their personal values. After all, as climate scientists know only too well, they will be suspected of bias however strictly they stick to the data.

This article appeared in print under the headline “Stand up and be counted”

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