Speaking te reo is "part and parcel" of being a New Zealander, a Northland high school principal says.
Ministry of Education figures show the number of secondary students taking te reo Maori are virtually unchanged from a decade ago.
Te reo enrolments peaked in 2008 at 26,339 students but slumped to 22,813 last year - a similar number to those learning French.
Tauraroa Area School principal Grant Burns said teachers and students were encouraged to use te reo every day at the school so the language was not a foreign concept.
"We believe that having some fluency and some ability to pronounce correctly is part and parcel of being a New Zealander."
Teachers used a "phrase of the week" and Maori language competitions were held weekly, Mr Burns said.
Learning a second language was also important for children's brain development, he said.
Public Service Association national secretary Brenda Pilott said public servants were now rewarded for Maori language competency.
"We have a number of collective agreements that specify an allowance for people who are competent in te reo and are using that as part of their work."
There was an increasing expectation that public servants could carry out some business in te reo, and it was important that they could respond competently, Mrs Pilott said.
Maori language immersion schools could be partly credited for the shift, she said.
Latest available census data from 2001 to 2006 revealed a drop in people's ability to hold an everyday conversation in Maori from 25.2 to 23.7 per cent.
Te reo Maori is not a compulsory part of the curriculum, but the Education Act requires schools to take "reasonable steps" to provide language instruction if it is asked for by parents.
"The New Zealand Curriculum Treaty of Waitangi principle sets a clear expectation that schools should provide opportunities for students to learn about Maori language and culture," an Education Ministry spokesman said.