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"It was a huge struggle. People would often look at us and say, 'You guys are so crazy'," she said.
"But the thing is, we supported each other. There were heaps of tears and arguments, but we soldiered on."
Part-time work, late nights and the support of parents and others saw the family through.
Mr Alatini eventually completed a Master of Arts in Pacific Studies from the University of Auckland, and now works as a Tongan language educator at the Pasifika Education Centre.
After completing her bachelors degree, Mrs Talakai-Alatini did postgraduate and then the two-year Master in International Tourism Management at the Auckland University of Technology.
This year she started a job running a diploma programme at the International Travel College of NZ's Botany branch, as well as teaching.
Next month will be a big one for the family. Mrs Talakai-Alatini will graduate on the 16th, and her fourth child - another girl - is due just 13 days later.
Nobody is prouder than Mr Alatini, who said he never doubted his "super-mum" wife.
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The dual decision to chuck in their jobs and return to study could seem crazy, he said, but "the timing is never right".
"If we kept waiting, there's never a right time for anything. So we just felt strongly about it, and decided to do it together."
Visit shows remittance value
Growing up in Mangere, Sio Talakai-Alatini always questioned the fact her parents sent money to relatives in Tonga. "That often puzzled me, because we were struggling here."
Mrs Talakai-Alatini was opposed to remittance until completing a thesis as part of her Masters in International Tourism Management at AUT.
As part of her project she travelled back to her family's village, Leimatu'a, in Tonga for the first time since leaving as a 3-year-old.
Witnessing the village reunion was a "full circle" moment, when she realised the kindness she was treated with and enduring bonds were a result of her parents' sacrifices.
"I now know why my parents did that ... it was a way that they looked at maintaining those relationships, and it was a sense of nurturing an obligation that they had for their families and extended families."
The visit also shed new light on childhood tales. Mrs Alatini said her mother often spoke fondly of her family's beautiful home.
"When I arrived ... it looked like a little shack. So now I know that she often romanticised about things back in her homeland. It was just fascinating."