Against the backdrop of early colonisation, on Sydney Harbour's shoreline, an extraordinary exchange took place between a young Aboriginal woman and a First Fleet Lieutenant.

This friendship serves as one of the earliest recorded cultural exchanges between Europeans and Aboriginal people, and the history and knowledge they documented together would be priceless.

Patyegarang, a young Gamaraigal woman who spoke the Gadigal language, would prove crucial to the survival of her Sydney-based native tongue.

William Dawes, an English Lieutenant and astronomer, recorded the pair's conversations, in what remains today the only known first-hand accounts of the Gadigal language.

Australia's first Aboriginal language teacher

Dawes set up an observatory at Point Maskelyne, now known as Dawes Point, where the southern pylons of the Sydney Harbour Bridge now stand.

The local Aboriginal people saw this spot as a safe and welcoming place to share friendship and knowledge.

It is here, a 15-year-old Patyegarang and Dawes likely developed their bond.

Dawes's notebooks clearly show that he and Patyegarang spent time in each other's company and shared emotion, humour, intellectual discussions and mutual respect.

Patyegarang became Dawes's chief teacher of language, with the two sharing details of their daily lives.

Melissa Jackson with Dawes's notebooks. ( Supplied: NSW state library )

Melissa Jackson, a Bundjalung woman and librarian and researcher at the NSW State Library, said while Dawes interacted with many people, it was Patyegarang that he spent most of his time with.

He even affectionately shortened her name to Patye.

"Patyegarang, through her close relationship with Dawes, certainly became a two-way method of communication and sharing," Ms Jackson said.

"She not only shared the Sydney language with Dawes in context but she learned English in a way that influenced Dawes in his dealing with authority and his refusal to participate in punitive actions taken against Aboriginal people and family groups.

"This definitely led to his recall to England even though he wanted to stay."

Patyegarang taught him words such as Putuwa, which means "to warm one's hand by the fire and then to gently squeeze the fingers of another person".

Other notable phrases include: Tariadyaou ("I made a mistake in speaking"); Minyin bial naadyimi? ("Why don't you sleep?"); and Minyin bial widadyemi ("Why did you not drink?").

She platonically shared Matarabaun nagaba, meaning "We shall sleep separately".

Book B, Page 30 of Dawes's notes where he refers to her as 'Patye'. ( Supplied: williamdawes.org )

Ms Jackson said this meant a dwelling with Dawes was comfortable enough for Patyegarang to take her clothes off — embarrassing him in the process — in order to quickly warm up by the fire ("Goredyu tagarin", she said).

Ms Jackson says there are slang words and expressions throughout the notebook that speak to her strength of character.

"At times rebellious, when she said after throwing the towel down in despair, 'Tyerabarrbowaryaou', meaning 'I shall not become white', when Dawes suggested that she could become white if she washed herself more."

Through the teachings of Patyegarang, researchers and historians have been able to identify some of the broader concerns of Aboriginal people of the time.

Dawes's notebooks make reference to the fact that Aboriginal people disapproved of the colonisation of their land and were afraid of the colonists' guns.

A trailblazing Aboriginal woman

There isn't much known about Patyegarang outside of Dawes's notebooks. However, history paints a stark picture as to how Aboriginal people were treated at the time.

For Patyegarang to teach a white man her way of life, showed both courage and conviction.

In the late 18th century, there were more than 250 distinct Aboriginal languages in use across the country. Today, all but 13 are categorised as highly endangered.

Director of Aboriginal and Torres Strait Islander Research at the University of Sydney, and proud Ngarigu woman, Professor Jakelin Troy has spent the three decades reconstructing Aboriginal languages of the Sydney area and says Patyegarang's interactions with Dawes have proved vital to the survival of Sydney's Gadigal language.

Professor Jakelin Troy said Patyegarang can be considered as the first Aboriginal linguist. ( Supplied: Jakelin Troy )

"The work that Patyegarang did with William Dawes produced the first field notes for an Australian language that provides sufficient information to reconstruct something of the verbal morphology (indicating something of the grammar and syntax) and lexicon (vocabulary) for any of our languages," she says.

Professor Troy says Patyegarang remains a profoundly important figure in Aboriginal and Torres Strait Islander history.

"Patyegarang can be considered the first Aboriginal linguist in Australia."

According to Professor Troy's research, there is evidence that as Dawes was learning the Sydney language from Patyegarang, she was learning English from him.

One anecdote in a notebook suggests that Dawes was also teaching her to read.

'A treasure trove of source material'

Dawes's notebooks on the 'Aboriginal Language of Sydney', from 1790-1791. ( Supplied: williamdawes.org )

Ms Jackson said although the Gadigal clan or family lived in the Sydney CBD, Patyegarang herself came from another part of the coastal region.

"She most probably, and we can't say anything for certain, came from what we now know as the North Shore which makes her Gamaraigal," she said.

"All of the clans of coastal Sydney spoke a language that they all understood, regardless of which clan they belonged to.

"Wherever she comes from, her persistence and patience with Mr D (as she called Lieutenant William Dawes) in sharing language and culture is the reason why we now have, in this time of pride in Australian languages, a treasure trove of source material for reviving the language."