But, efforts are being made to redress the loss.
It's been more than 25 years in the making but a dictionary has been launched showcasing their native language.
"This is a historical and proud time for me and for all of us, I know there are a lot of very, very proud people," Elvie Dann said.
At a ceremony in the remote Murchison Settlement, about 200 kilometres north of Mullewa, more than 200 people gathered to celebrate the dictionary which is hoped will revive the language that has all but been forgotten.
Started by the Bundiyarra-Irra Wangga Language Program, the book has over 2,500 entries compiled by more than 100 elders, linguists and community members.
Captured for the future
Vaso Elefsiniotis began her work on the dictionary in 1999, as a linguist for the Yamaji Language Council.
She says it is extremely important the language is preserved.
"There are still strong speakers and one of the reasons for doing the dictionary is to capture as much language as possible and put it in a written form for this generation and future generations," she said.
"It's not just the younger generation, it's the current, middle-aged generation that missed out on the language as well.
"I was predominately working with people in their 60s and 70s whose children grew up in an era where native language was forbidden.
"Many were flogged and were punished for speaking the language."
"The government's decision created a big gap and that's the wonderful thing about this dictionary.
"It's there for the children to close that gap, it's heritage passed on.
"I'm sure they're going to be proud about this dictionary, especially if they see a family member's name in the credits."
During the compilation of the dictionary, linguists took elders to remote Wajarri communities such as the Williams station, and recorded Wajarri songs and language.
Godfrey Simpson, who works for the Bundiyarra-Irra Wangga Language Program, was part of this process.
"The freedom of being on home country meant so much to the elders which meant that a lot of great work was done in those sessions," he said.
"I would be lost without a language centre to go to.
"It's an honour and privilege to learn my father's language and I'm even more privileged to have learnt it from his parents, my grandparents."
Elvie Dann's mother is a highly respected elder in the Wajarri community who worked on the dictionary in the late 80s when it was little more than an idea.
"My mum spent much time with the linguists," she said.
"She didn't even know how to read or write but she was out there in the bush giving information to the anthropologists."
The next generation
Ms Elefsiniotis says she hopes the dictionary will encourage the language to be taught at schools in the Mid West and Murchison regions.
"You've got a really important tool to encourage people to put their hands up to be teachers because we need more language programs in the schools," she said.
"Back in the 90s there was a resurgence in training people to be teachers of Wajarri.
"Although those language programs have continued, there are no new teachers coming through the system."
There is support at a federal Level to revive Indigenous languages nationally.
Shayne Neumann is a Federal MP and the head of a parliamentary committee on Aboriginal and Torres Straight Islander affairs.
He says before white settlement, there were hundreds of native languages, now there are only about 20.
"If you've lost your language and you can't speak, you lose your identity and if you feel isolated and not part of our community you can consequently do things that aren't acceptable in our community," he said.
"Even the ones that have been lost we think we can revive; for example, the most successful revival of a language was say, Hebrew in Israel.
"This is an extremely important issue not just for Indigenous people but for all Australians."
Ms Elefsiniotis says the hard work for the Wajarri dictionary was worth it in the end.
"It did take a lot of time and effort," she said.
"But the Oxford English Dictionary took nearly 70 years for the first edition to be published and that's one of the most famous language dictionaries in the world.
"This is a milestone.
"Elders insisted the dictionary had to be launched on Wajarri land, it's so special to be on Wajarri country.
"It's really important that a launch like this happen on this country."
Wajarri elder Elvie Dann plans on showing the finished book to her mum, who suffers from dementia.
"She'll be excited when I show her the dictionary, her face will just light up, it will be exciting for her to see," she said.
"I'm just proud that I was a part of this, I just feel a great sense of pride, especially on behalf on my mum."