OPINION: Recently my own prejudices, buried so deep I had no idea they were even there, reared their head.

It was a 'meet the newly enrolled families' evening at the local Playcentre and there was a Chinese-born mum and dad with their baby boy, and the boy's grandmother, who would be taking him to the sessions.

The grandmother couldn't speak much English, and, ashamed as I am to admit it, I began to wonder what, if any, contribution she could make to our little group of young, mostly white and English speaking mums.

Amy Bell Photography Tommy (left) and Henry Cully.

Come the first day of term there she was, proudly beaming with her grandson, 10-months old and a gorgeous blob of blue-black hair and dimples to die for.

She introduced herself as Nai Nai, the Mandarin word for grandmother, and plopped little Ray ("I call him Ray Ray") on the floor with my twin boys, who were roughly the same age.

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Over the days and weeks I watched Nai Nai struggle with Ray Ray as he went through all the usual baby things that drive us all mental – teething, fussiness, tiredness from skipping naps and refusal to try new foods.

But twice a week, every week, she fronted our little group, always with a smile, and the effort she made to learn my boys' names – and to tell apart the identical twins – was second only to the effort she made to be the world's best grandparent.

And she did it all on her own, her son and daughter-in-law, whom she lives with, both work full-time as they build a new life for themselves and their child in New Zealand.

In broken, stunted English she would offer to make me a cup of tea or scoop up a twin when they cried. One hellish day when my toddler threw the mother all tantrums and I burst into a flood of frustrated tears she was there to give me the warmest and most comforting hug I've felt in a long, long time.

That was the first time I cried in front of Nai Nai. The second was even more personal, for both of us.

It was when she brought her grandson over to me, sat him at my feet and shyly handed me a picture book.

"Read to him, please", she asked. "I want him to learn English. He can't from me."

And there it was, the secret of all overseas-born grandparents the world over who give up everything, their own brothers and sisters back home, their independence, their everything to look after grandchildren.

They do it so their sons and daughters can work or study full time (and keep the economy running) and avoid insanely expensive childcare options.

They do it because they love their grandchildren so much they are willing to live in a country where they can't understand a lot of what is being said or written around them, but march on nonetheless.

And, in the case of Nai Nai, they do it knowing that even if they can't teach their grandchild English they will do whatever they can to make sure someone else can.

So next time some bigot masquerading as a politician goes off on a rant about how they don't hear English spoken in playgrounds any more, or if you catch yourself, as I did, wondering what value they can add to country where they don't read or speak the local language, or work, think of Nai Nai and Ray Ray.

Because I guarantee you wee Ray Ray will grow up to be a bright and beautiful Kiwi and the type of person New Zealand will be proud to claim as its own.

Xiè xie Nai Nai.