Scotty Morrison was "sliding into the wrong side of life", before te reo Māori brought him back. Now he is expending all his energy on passing that gift on.
"I was a bit haututū," Morrison said.
"Getting into a bit of mischief. Te reo gave me purpose, something to be passionate about. Now I am trying to pay back the gift the Māori language has given me."
Morrison is a professor of te reo Māori at Massey University and a news presenter on TVNZ current affairs shows Te Karere and Marae.
He has also written several te reo Māori books including his most recent, Māori Made Easy 2, following on from the hugely successful Māori Made Easy.
Like the first edition, Māori Made Easy 2 provides daily 30-minute lessons over 30 weeks. This edition dives deeper into the intricacies of te reo.
"The books are designed to keep continuity between formal and home learning, so when you go back to the night class you are two steps ahead, rather than taking a step back."
Unlike many of his devoted students, Morrison, of Ngāti Whakaue descent, "fell into" te reo, by accident.
He didn't grow up with it in his Rotorua home, nor was it spoken in his wider family.
When he started teachers' training college, he took an introduction to te reo paper, but only to suit a timetable that would give him a three-day weekend.
"It is not a great 'saw the light' kind of story."
In his second year he joined a flat with some of his fluent speaking classmates.
"By the third night I realised I was in a total immersion environment."
He decided to stay and found the colloquial style language at home and more formal style at university had him progressing rapidly.
"By the end of the year I saw The Matrix."
Morrison uses the movie reference to describe when language learners click, and can understand and respond.
"Like when the spies are firing bullets at Neo and it all slows down. It was the same thing. overnight I came out of my room, a flatmate said something to me in Māori and I responded."
From there Morrison's passion for te reo grew, and being exposed to mentors like Sir Timoti Karetu and Wharehuia Milroy made him motivated to take it even further.
As a tertiary-level reo teacher for over 25 years, Morrison has seen a massive growth in interest.
"It is fantastic. Now there is a lot of goodwill and attitude towards te reo, and a lot has only happened in the last five years.
"We owe a lot to our language champions in the 1970s and 1980s who got the kohanga reo and te kura kaupapa Māori movements going.
"Now we have champions in mainstream New Zealand, like Jack Tame and Guyon Espiner. We need more people like them making it normal."
"This year the top students at Massey have been a French girl and a guy from Middle East - they are already trilingual, have opened up their neurological pathways.
"They also don't bring any of that historical baggage into the classroom, which some Māori have, trauma with the reo. The shame and embarrassment of feeling a strong affinity, but not being able to speak it."
At TVNZ he and wife Stacey Morrison have been running introductory te reo classes.
"We had 40 spaces, and we got 400 responses."
Despite the massive growth in learners, the rate of fluent speakers was gradually declining.
"We are getting good normalisation but we are losing a lot of native speakers and not replacing them," Morrison said.
He had come round to the idea of compulsory te reo in schools after seeing language revitalisation in Ireland and Wales, but "it has to be planned out with the right teaching and resources".
One of the main barriers to learning - like any language - is persisting.
"You need to work out how to fit it into your busy schedule, formulate a plan, make contact with people in the reo space who can kōrero with you."