There is one expression I have grown up hearing from relatives of a certain age, but never been able to accept. It’s the description of Twi – the Akan language spoken by my family – as “the vernacular”, a term which implicitly compares it with the colonial language, English, and somehow finds it wanting. The word itself is a revealing symptom of the colonial project. Just as nations like the Yoruba, with a population of more than 40 million, were patronisingly described as “tribes”, when in fact they were substantial nations, African languages were downgraded to “the vernacular”. It’s a term more befitting of a regional dialect than a nation’s language, with its own history, politics and literature.

The attempt to discourage Africans from speaking our own languages not only failed, but has had the glorious result of backfiring, to the extent that now Britain’s own inhabitants are officially adopting African vocab. This month the Oxford English Dictionary (OED) added Nigeria’s first entries to already recognised gems like “howzit” from South Africa. Other Africans will recognise lots of the latest lingo to get the OED stamp – “chop”, to eat or to misappropriate funds; “next tomorrow”, the day after tomorrow; “sef”, a great Pidgin flourish for emphasis.

Nigerian pre-eminence in the English language is nothing new. One of the first global literary successes by a black author was The Interesting Narrative, by the Igbo writer Olaudah Equiano, the beautifully written 1789 account of his enslavement and subsequent freedom.

As a Booker prize judge last year, I was struck – although not surprised – by just how many entries there were from Nigerians, with two on the longlist, and the joint winner, Bernadine Evaristo, of Nigerian heritage. The sheer number of legendary authors from the nation makes it often overrepresented in the English canon. But Nigeria’s relationship to the English language, like that of all English-speaking African nations, is a complicated one. Chinua Achebe – one of the legends – wrote of the English language, “we may go on resenting it, because it came as part of a package deal that included many other items of doubtful value, especially the atrocities of racial arrogance and prejudice which may yet set the world on fire … If [English] failed to give them a song it at least gave them a tongue for sighing.”

English was imposed on Africans by force. “In Kenya, English became more than a language: it was the language, and all the others had to bow before it in deference,” wrote the great Kenyan novelist Ngũgĩ wa Thiong’o. In his seminal book Decolonising the Mind, he described children at his English-speaking school in Nairobi being beaten if they were caught speaking Gĩkũyũ.

One of my favourite grievances with that colonial legacy, and the ongoing failure to give the descendants of empire equal status, came via the unlikely topic of weather systems. “Yo why storm Brendan?” wrote the doctor and TV presenter Dr Ronx earlier this month, “I’m out here waiting to be blown away by storm Oluwatunde! We need to decolonise storm names!” Why storms always have European names can be added to a growing list of questions: why don’t British schools teach the history of empire; why does it have no national museum; why do we glorify colonial violence as personified by figures like Cecil Rhodes; why do we know the name of William Wilberforce but not Equiano, a key abolitionist as well as celebrated author?

The great thing about language though, is that it waits for no one. While calls to decolonise curricula – and weather – seem likely to continue falling on deaf ears, culture moves on. Several years ago I wrote about how the situation of “the Queen’s English” in Ghana – once associated with superior education and intelligence – has become more perilous, with the potential to attract derision under the acronym LAFA – locally acquired foreign accent.

Not just English but other European languages are finding their centre of gravity shifting to Africa. Portuguese currently has its greatest number of speakers in Brazil – where Yoruba and indigenous languages have moulded vowels and expressions utterly different from the language of Portugal – but some believe that by the end of the century, the growth of Angola and Mozambique will make Africans the most numerous speakers of Portuguese. The history of colonialism by France and Belgium means that since 2010, 68% of the world’s new French speakers now live in West and Central Africa. The African capacity to survive the brutality of colonialism means French is now the fifth most widely spoken language in the world.

The paradox of empire is perhaps most visible in its legacy of language. The psychology of colonisation could not have worked without suppressing expressions of existing culture, and “educating” its subjects to believe in their own inferiority. But the independence of the African continent in the 20th century could not have come about when it did without the unity that was forged out of common languages brought by colonisers – English, French and Portuguese. The resulting ambivalence towards English is shared not just on the African continent but in the diaspora as well. As the great African-American writer James Baldwin once wrote, “my quarrel with the English language has been that the language reflected none of my experience”. But, Baldwin conceded, “it might be made to bear the burden of my experience, if I could find the stamina to challenge it.”

His words reflect a fatigue with the colonial story, which I often share. But at the same time, we always did find the stamina to challenge it, whether or not that was recognised by dictionaries.

• Afua Hirsch is a Guardian columnist