- Estimated number of Aboriginal languages spoken in Australia before invasion. 
- Estimated number of dialects spoken in Australia before invasion. 
- Number of Aboriginal languages considered 'alive' and in use as a first tongue today. 
- Percentage of Aboriginal people mainly speaking an Aboriginal language at home in 2008, unchanged from 2002.  75% of these can also speak English. 
- Percentage of Aboriginal people in some remote areas of Australia who speak an Aboriginal language at home. 
- Percentage of Aboriginal adults who identified with a clan, language or tribal group in 2008. Same figure in 2002: 54%. 
- Number of people in NSW who identified as speaking an Aboriginal language in the 2006 census. Same figure in 2002: 2,682. 
- Percentage of surveyed West Australians who support the inclusion of Indigenous languages as part of the school curriculum. 
- Number of Aboriginal languages spoken in Australia in 2010. 110 of them are "critically endangered". 
- Estimated number of Aboriginal languages still spoken in 2014. Of those, 13 were considered 'strong' and about 100 'severely' or 'critically' endangered. 
- Number of Aboriginal languages and dialects spoken in New South Wales before the arrival of Europeans. 
- Number of Aboriginal languages spoken in New South Wales today. 
- Number of Aboriginal languages in NSW considered healthy enough to be included in school curricula. 
- Number of Aboriginal people whose mother tongue is an Aboriginal language. People who speak Yolngu: 6,000, Arrernte: 3,000, Warlpiri: 3,000. 
- Number of Noongar people who speak Noongar. Total number of Noogar people: 40,000. 
List of articles
When I speak language, it makes me feel [at] home.— Roger Hart, Aboriginal elder 
I think that Australia holds one of the world's records for linguicide, for the killing of language.— Prof Ghil'ad Zuckermann, linguist, Adelaide University 
Traditional hand signs & sign language
You'll be quick to agree that when Aboriginal people were out hunting they couldn't just call out to each other—it would have scared away their game. So they used an intricate sign language to signal to each other.
- Mourning. During extended periods of mourning women (but not men) of the Warumungu and Warlpiri used signs instead of speech, sometimes for longer than a year. Speech was also culturally forbidden during periods of mourning for the Yolŋu people of North East Arnhem Land.
- Ceremony. During certain ceremonies speaking might be forbidden.
- Long-distance communication. Sign language is used when communicating over a large distance as talking out loud is considered inappropriate. Using sign language during hunting would also fall into this category.
- Confidential or secret information. When trying to avoid being overheard sign language is also used. I've experienced this first-hand when I was travelling with a backpack with an Aboriginal flag on it. In a restaurant, I could see a young couple gesticulating with each other while looking at my backpack.
- Sacred information. When referring to ceremonial issues, objects and sites Aboriginal people use sign language to codify or obscure the restricted information.
- Adding emphasis. Sign language is also used to add emphasis to verbal speech (which many non-Aboriginal people do as well).
- Wrong skin. Yolŋu people are not allowed to talk in the company of "poison kin", people of a different group where cultural protocols dictate that they cannot talk to them.
In the Western Desert areas men use sign language more than women, mainly ceremonially in initiation rituals or during hunting.
Sign languages have been used throughout the dry inner Australian areas as well as in northeast Arnhem Land and western Cape York. 
Most sign languages studied were found to be closely related to the spoken language, thus foreign to other Aboriginal nations.
Adam Kendon is considered an expert in this area with his stellar work Sign Languages of Aboriginal Australia.
Hand signs are considered one of two competing ideas about how early humans developed language.  In an experiment with university students, who were not allowed to use language, they became fluent very quickly in a sign language they developed, rather than the use of vocalisations.
Clifton Bieundurry explains more about the many uses of sign language in the following video.
Case study: Yolŋu Sign Language
Yolŋu Sign Language (YSL) is an endangered sign language of the Yolŋu people of North East Arnhem Land in the Northern Territory. 
YSL is the primary language of Yolŋu who are deaf, but not a signed version of the locally spoken language. It is an alternate language for those capable of hearing. Linguists refer to this as "multilingual bimodalism of alternate sign languages", and label people who can communicate in both spoken and signed languages as "bimodal-bilingual". It is quite common among Aboriginal nations.
70 signs of YSL, first documented in 1929, are still in use today.
A book, The Illustrated Handbook of Yolŋu Sign Language of North East Arnhem Land, aims to teach YSL to young children in an effort to preserve this language.
23 September is the International Day of Sign Languages.
Aboriginal language: When yes means no
Sometimes people say 'no' when they mean 'yes'. But it might surprise that many Aboriginal people say 'yes' and mean 'no'.
Research uncovered that Aboriginal people often answer 'yes' to advances by salespeople to appease the salesperson and politely end the conversation.  Salespeople however took their 'yes' as agreement and sealed the contract with dire consequences.
Hundreds of Aboriginal people entered unintentionally into exploitative, unfair contracts to buy, lease or lay-by products and services they can't afford and don't understand. The North Queensland-based Indigenous Consumer Assistance Network (ICAN) cancelled more than 800 contracts, preventing an estimated $2 million of financial detriment,  which they consider the "tip of the iceberg".
Similarly, Aboriginal people "agree" in everyday conversations with non-Indigenous people. They try to politely tell the person that they do not want or can't answer their questions or request because they haven't built enough trust yet or it is not their call to reveal the answers.
If you are interested in researching Aboriginal languages check out the following websites.
Indigenous communities are as diverse as Indigenous languages.— Jimmy Pascoe, traditional owner, Maningrida, West Arnhemland, Northern Territory 
Gambay - First Languages map
First Languages Australia has developed a map of Australia’s first languages and language families that reflects the names and groupings favoured by Aboriginal communities.
You can search by language or town and share the information about each language. Videos illustrate languages or give samples. The site allows language centres and communities to update information as needed.
Dharug Dalang is a site launched in October 2010. It features hundreds of words, some of which are read out to you so you can learn their pronunciation.
The site has also background information and video interviews about language of Aboriginal people.
Check it out: www.dharug.dalang.com.au.
Living Archive of Aboriginal Languages
This open access archive from the Charles Darwin University contains more than 3,600 items of authentic texts in 50 Aboriginal languages of the Northern Territory, many with English translations and illustrations, and all available to read or download for free. The materials cover a vast array of topics, from traditional stories, ethnobiology, history, bush food and medicine, tales of contemporary life, and translations of English stories.
Visit the Living Archive of Aboriginal Languages.
Australian Institute of Aboriginal and Torres Strait Islander Studies (IATSIS)
IATSIS' Australian Indigenous languages database AUSTLANG allows you to search for Aboriginal languages by name, place name or by navigating Australia through Google Maps.