Stephen is an interdisciplinary/transdisciplinary scholar whose work traverses education, applied linguistics, sociolinguistics, sociology, and political theory, with a specific focus on language and equity. He has written widely on language policy, language rights, language revitalization, and language education (especially, Indigenous, bilingual, immersion, and multilingual education).

Additional research interests are in critical ethnography, critical social theory (particularly the work of Bourdieu), critical race theory, critical multicultural approaches to education, and the wider politics of multiculturalism, ethnicity, and nationalism.

He has acted as a Research Consultant and/or an Expert Witness for the following:

Academic Consultant, RITA-RÄNNE, Estonia (2018-2020)

Academic Consultant, McREL International, Federated States of Micronesia (2019)
Academic Consultant, ADRA Myanmar, Strengthening ethnic education for the Karen Indigenous peoples (2015)
National Expert (NZ), Migrant Integration Policy Index (MIPEX (http://www.mipex.eu/)) (2013)
Expert Witness (language rights), AOCP v. Lamoureux, Supreme Court, Canada (2012-2013)
Expert Witness (bilingual education) Wai 2336, Te Kōhanga Reo Trust, Waitangi Tribunal Claim (2011-2012)

In the public eye

Stuff NZ: https://www.thepost.co.nz/nz-news/350124740/ok-monolingual-boomer-you-might-be-having-your-final-moment-sun December 2023

Newsroom. Dismissing mātauranga Māori. Racism and arrogance in academia (https://www.newsroom.co.nz/ideasroom/dismissing-matauranga-maori-racism-and-arrogance-in-academia). August 2021

Stuff NZ. Does speaking two languages make you smarter? (https://www.stuff.co.nz/national/maori-language-week/115638522/does-speaking-two-languages-make-you-smarter-its-easier-to-learn-more-when-you-already-know-two). September 2019

RSNZ. Why doesn't te reo Māori have more prominence in English-speaking New Zealand? (https://www.royalsociety.org.nz/research/can-te-reo-maori-gain-more-prominence-in-english-speaking-new-zealand/). July 2018

Newsroom. To all te reo Māori haters out there (https://www.newsroom.co.nz/@future-learning/2017/11/30/64423/to-all-te-reo-mori-haters-out-there). December 2017

Newsroom. Why no one wants to teach in New Zealand (https://www.newsroom.co.nz/@future-learning/2017/08/09/41927/why-no-one-wants-to-teach-in-new-zealand). August 2017

Conferences

- Stephen was the co-convenor, with Prof. Gary Barkhuizen, of the Sociolinguistics Symposium 22, held at the University of Auckland, 27-30 June 2018 with circa 1000 delegates from over 60 countries. The biennial Sociolinguistics Symposium is the premier international conference in its field and this was the first time it was held both outside of Europe and the Northern Hemisphere.

- Stephen also convened the quadrennial international conference series, Language, Education and Diversity (LED). There have been four previous LED conferences, held in 2003, 2007, 2011, and 2015, which have all attracted circa 500 delegates.