[8] Most Australian languages belong to the widespread Pama–Nyungan family, while the remainder are classified as "non-Pama–Nyungan", which is a term of convenience that does not imply a genealogical relationship.
In the late 18th century there were more than 250 distinct First Nations Peoples social groupings and a similar number of languages or varieties.
For convenience, the rest of the languages, all spoken in the far north, are commonly lumped together as "Non-Pama–Nyungan", although this does not necessarily imply that they constitute a valid clade.
Dixon argues that after perhaps 40,000 years of mutual influence, it is no longer possible to distinguish deep genealogical relationships from areal features in Australia, and that not even Pama–Nyungan is a valid language family.
For example, Kenneth L. Hale describes Dixon's scepticism as an erroneous phylogenetic assessment which is "such an insult to the eminently successful practitioners of Comparative Method Linguistics in Australia, that it positively demands a decisive riposte".
[18] Hale provides pronominal and grammatical evidence (with suppletion) as well as more than fifty basic-vocabulary cognates (showing regular sound correspondences) between the proto-Northern-and-Middle Pamic (pNMP) family of the Cape York Peninsula on the Australian northeast coast and proto-Ngayarta of the Australian west coast, some 3,000 kilometres (1,900 mi) apart, to support the Pama–Nyungan grouping, whose age he compares to that of Proto-Indo-European.
Johanna Nichols suggests that the northern families may be relatively recent arrivals from Maritime Southeast Asia, perhaps later replaced there by the spread of Austronesian.
[19][20][21] For a long time unsuccessful attempts were made to detect a link between Australian and Papuan languages, the latter being represented by those spoken on the coastal areas of New Guinea facing the Torres Strait and the Arafura Sea.
[22] In 1986 William A. Foley noted lexical similarities between Robert M. W. Dixon's 1980 reconstruction of proto-Australian and the East New Guinea Highlands languages.
He believed that it was naïve to expect to find a single Papuan or Australian language family when New Guinea and Australia had been a single landmass (called the Sahul continent) for most of their human history, having been separated by the Torres Strait only 8000 years ago, and that a deep reconstruction would likely include languages from both.
In fact, it seems quite possible to explain the multiple forms of languages in Australia on the basis of a single original."
Tasmania had been separated from the mainland at the end of the Quaternary glaciation, and Indigenous Tasmanians remained isolated from the outside world for around 12,000 years.
[27] In 1990 it was estimated that 90 languages still survived of the approximately 250 once spoken, but with a high rate of attrition as elders died out.
[30] During the period of the Stolen Generations, Aboriginal children were removed from their families and placed in institutions where they were punished for speaking their Indigenous language.
Warrgamay/Girramay man Troy Wyles-Whelan joined the North Queensland Regional Aboriginal Corporation Language Centre (NQRACLC) in 2008, and has been contributing oral histories and the results of his own research to their database.
[45] The project is co-ordinated by Nick Thieberger, who works in collaboration with the National Library of Australia "to have all the microfilmed images from Section XII of the Bates papers digitised".
[50] The language had rapidly disappeared after the settlement of South Australia and the breaking up of local indigenous people.
There are also commonly speech taboos during extended periods of mourning or initiation that have led to numerous Aboriginal sign languages.
[52] A typical Australian phonological inventory includes just three vowels, usually /i, u, a/, which may occur in both long and short variants.
[55] In the few cases where fricatives do occur, they developed recently through the lenition (weakening) of stops, and are therefore non-sibilants like [ð] rather than the sibilants like [s] that are common elsewhere in the world.
Besides the lack of fricatives, the most striking feature of Australian speech sounds is the large number of places of articulation.
The four-way distinction in the coronal region is commonly accomplished through two variables: the position of the tongue (front, alveolar or dental, or retroflex), and its shape (apical or laminal).
[52] A language which displays the full range of stops, nasals and laterals is Kalkatungu, which has labial p, m; "dental" th, nh, lh; "alveolar" t, n, l; "retroflex" rt, rn, rl; "palatal" ty, ny, ly; and velar k, ng.
A notable exception to the above generalisations is Kalaw Lagaw Ya, spoken in the Torres Strait Islands, which has an inventory more like its Papuan neighbours than the languages of the Australian mainland, including full voice contrasts: /p b/, dental /t̪ d̪/, alveolar /t d/, the sibilants /s z/ (which have allophonic variation with [tʃ] and [dʒ] respectively) and velar /k ɡ/, as well as only one rhotic, one lateral and three nasals (labial, dental and velar) in contrast to the 5 places of articulation of stops/sibilants.
Kunjen and other neighbouring languages have also developed contrasting aspirated consonants ([pʰ], [t̪ʰ], [tʰ], [cʰ], [kʰ]) not found further south.
These descriptions do not apply exactly to all Australian languages, as the notes regarding Kalaw Lagaw Ya demonstrate.
Heterorganic nasal + stop sequences remain stable even in modern connected speech, which is highly unusual.
This pressed quality could therefore serve to enhance the clarity of speech and ensure the perception of place of articulation distinctions.
[57] Probably every Australian language with speakers remaining has had an orthography developed for it, in each case in the Latin script.
Sounds not found in English are usually represented by digraphs, or more rarely by diacritics, such as underlines, or extra symbols, sometimes borrowed from the International Phonetic Alphabet.