There are also numerous people from other parts of the world now resident, including Chinese,Europeans, Australians, Filipinos, Polynesians, and Micronesians (the last three belonging to the Austronesian family). Around 40,000 expatriates, mostly from Australia and China, were living in Papua New Guinea in 1975.

Papua New Guinea has more languages than any other country, with over 820 indigenous languages, representing 12% of the world's total, but most have fewer than 1,000 speakers. The most widely spoken indigenous language is Enga, with about 200,000 speakers, followed by Melpa and Huli. Indigenous languages are classified into two large groups, Austronesian languages and non-Austronesian, or Papuan, languages. There are three official languages for Papua New Guinea: English, Tok Pisin, and Hiri Motu.

English is the language of government and the education system, but it is not spoken widely.

The primary lingua franca of the country is Tok Pisin (commonly known in English as New Guinea Pidgin or Melanesian Pidgin), in which much of the debate in Parliament is conducted, many information campaigns and advertisements are presented, and until recently a national newspaper, Wantok, was published. The only area where Tok Pisin is not prevalent is the southern region of Papua, where people often use the third official language, Hiri Motu.

Although it lies in the Papua region, Port Moresby has a highly diverse population which primarily uses Tok Pisin, and to a lesser extent English, with Motu spoken as the indigenous language in outlying villages. With an average of only 7,000 speakers per language, Papua New Guinea has a greater density of languages than any other nation on earth except Vanuatu.