It emerged in the late 19th century amongst indentured labourers, mostly from the Bismarck Archipelago, sent to work on German-owned plantations in Queensland and, especially, Samoa.

Many of these workers, speaking vastly different mother tongues, only shared in common simplified English vocabularies they would have picked up from English-speaking traders back home, and so used this to communicate with one another.

These vocabularies would eventually combine with random words taken from German, Samoan, and various Bismarck languages, and become standardised over time into a pidgin language used in and amongst the labourers, who would apply their own native grammatical rules to the wordset.

When the workers eventually returned home to the islands, the pidgin came with them, and continued to develop as a Papuan lingua franca, eventually spreading across most of is now Papua New Guinea.

With increased use, the wordset continued to expand and the language became more complex.  With the advent of urbanisation in the post-war era and the flocking of people from around the country to major urban centres such as Port Moresby and Lae, intermarriage between people of different ethnic backgrounds became common, and often Tok Pisin was the only language couples had in common.

Thus, Tok Pisin was the language they spoke around the household and passed onto their children, assuring its continued survival and further development.

Ethnologue places the number of people using Tok Pisin as a mother tongue at 122,000 as of 2005, with 50,000 of these speakers monolingual; the former number is rapidly growing and may be as high as one million people.

The number of speakers who use Tok Pisin as a second language, is a rather large four million people out of a national population of seven million. Use is common among the expatriate community; Radio Australia even maintains a Tok Pisin service.

Hiri Motu, on the other hand, never developed into a full creole and has experienced a precipitous decline in usage in recent years. Hiri Motu predates European contact; it likely developed as a trading language between the Motu people of southeastern New Guinea (the area now containing Port Moresby) and their neighbours along the coast as a simplified version of the Motu language (a hiri was a Motu trading mission along the Gulf of Papua).

Use of Hiri Motu took off in the early 20th century colonial period when British authorities in the Territory of Papua adopted the pidgin to communicate with the Motu, giving the language its alternate name of ‘Police Motu’.

Due in part to the influence of the capital city of Port Moresby, Hiri Motu was the major lingua franca in the southern portions of the country, peaking in use in the 1960s before being supplanted by Tok Pisin.

Today, use of the language is limited (around 120,000 in 1989 and declining), and most users are elderly. Even most Motu people no longer use it.