WELLINGTON, New Zealand — Prime Minister Jacinda Ardern of New Zealand has pledged that her newborn daughter would grow up to learn both English and the country’s indigenous Maori language, which is battling for survival after years of decline.

Ms. Ardern’s first child, Neve Gayford, was born on June 21, and the prime minister returned to work last week after six weeks of parental leave. As one of only two modern world leaders to give birth while in office, each decision she makes about raising her daughter is being watched and discussed by a global audience.

In an interview on Monday with Maori Television, Ms. Ardern said that she “certainly” wants her daughter to speak Maori.

Maori, or “te reo Maori” as it is widely rendered in New Zealand, is one of the country’s three official languages — along with English and New Zealand Sign Language — but it is thought only about 125,000 of the country’s 4.7 million people, or about 2.5 percent, speak it.