Distinctive Features - Speech Resource Pages - Macquarie University

) Centring Diphthongs
Mitchell (1946) lists three centring diphthongs for Australian English: /ɪə/,/ɛə/ and
/ʊə/.
There was also a possible 4th centring diphthong /oə/ which appears to have
been described for Australian English by McBurney (1887), although we have no
way of knowing whether words like "poor" [poə] were pronounced as one or two
syllables and therefore as a diphthong or as two monophthongs. This fourth
centring diphthong is occasionally described for some varieties of British English
(eg. Wells, 1982). Further, Bernard (1970, 1986) found that 22 out of 112 /oː/
vowels produced by Australian speakers in an /h_d/ context had an "inglide" (ie.
[oə]). Bernard considered this inglide to be no more than an idiosyncratic or
allophonic variant of the phoneme /oː/ and no phonetician argues for the
existence of /oə/ as a phoneme in modern Australian English.
The continuing existence of /ʊə/ as a phoneme in Australian English is doubtful. It
was confidently described by Mitchell (1946) and most phoneticians up until the
1960's to be a phoneme of Australian English realised as a centring diphthong
[ʊə]. Its status as a phoneme in Australian English has become quite unclear in
recent years. If it still exists, it is a very low frequency phoneme. There is a lot of
idiosyncratic variation in the survival of diphthongal realisations of this phoneme
(those that still possess an audible or measurable in-glide). Even words such as
"tour", which have often been cited as late survivors of words containing /ʊə/ are
nearly always now found to contain either [oː] (a monophthong) or [ʉːə] (two
monophthongs, ie. two syllables).
Of the remaining two centring diphthongs, only /ɪə/ (a) is common and (b) is
produced as an in-gliding diphthong by a majority of Australian English speakers
(but a fairly large minority are now pronouncing it as [ɪː]).
The phoneme previously labeled /ɛə/ or /eə/ is now produced as a long mid-high
monophthong [eː] by the majority of Australian English speakers in CVC contexts
(e.g. "paired") and has been transcribed phonemically by most Australian English
phoneticians as /eː/ since the early 1990's. It should be noted, however, that
there is evidence that the same people who pronounce it as [eː] in a CVC context
pronounce it as [eə] in CV contexts (e.g. "hair").
Why is this discussion of centring diphthongs of relevance to the current topic?
The answer lies in the extent to which the centring diphthongs can be accounted
for by the features used in tables 1 and 2 if they undergo the process of
monophthongisation.
The inclusion of /eː/ in the list of Aus.E. monophthongs causes no problem for this
system of distinctive features. /eː/ is simply the tense equivalent of the lax vowel
/e/ and the tenseness of /eː/ is realised phonetically as either a long vowel or as
an offglided diphthong (varying with speaker and phonetic context). If this
system of distinctive features has any cognitive validity, it might help explain the
reason why /eː/ has evolved from the earlier /eə/ vowel described by Mitchell in
the 1940's whilst /ɪə/ has been resistant to such a change. It might also explain
why /ʊə/ and a possible earlier diphthong /oə/ have disappeared (either by
merging with an existing tense monophthong, or by splitting into a sequence of a
tense monophthong plus schwa). In table 2 there was a vacant slot for /eː/ and, if
this distinctive feature model is correct, there was therefore nothing to prevent
the diphthong from surviving the process of monophthongisation by becoming a