Wednesday, 23 February 2011

An Experiment in English Phonology

We normally think of English as having voiceless stops, /p t k/ and voiced stops, /b d g/. Voiceless stops have an aspirated allophone [p_h t_h k_h] that appears in certain places, particularly when the stop appears at the beginning of a syllable. Aspiration, in this model of English pronunciation, is a redundant secondary feature of voiceless stops.

However, on the Conlang Mailing List, And Rosta proposed an alternative model. His idea is that English actually has aspirated stops /p_h t_h k_h/ and unaspirated stops /b d g/. Voicing would be a redundant secondary feature of unaspirated stops - the [t] in "stop" would actually be a /d/ that's lost its voice. And put forward a number of interesting theoretical arguments for this, but I thought that it needed to be tested experimentally.

If the standard interpretation of English phonology is correct, English speakers should find voiced and voiceless stops easier to tell apart than aspirated and unaspirated stops. In And's interpretation, they should find aspirated and unaspirated stops easier to tell apart than voiced and voiceless.

Bengali distinguishes between plain (voiceless, unaspirated), apsirated, voiced and voiced aspirated (breathy voiced or murmured) stops. I asked a Bengali speaker to record a sample of 20 words which you can listen to here and transcribe them in CXS. I then asked three volunteers from the Conlang Mailing list, all of whom were monoglot English speakers, to listen to the recording, and trascribe their first impression of what they heard. Here are the results.

OriginalListener 1Listener 2Listener 3
kat`_hdaptatdat_h
k_habarkabarkabark_habal
gajokdajukgAijokd_haIVlk_h
g_tOt`ona@_^k_hot7naxor\tunAk_h7dn@
tSabicabitS)Abitzabin
d`_told_<toltolpoUil
p_hulpUlpulpul
panibanibAnibani
d`imbimbimdin
tarad`al`atAr\Ada4a
t_hakatakatakataka
dipdipdipdip
bat`ibadibA'tibadi
aSar`_haSar\as`Ar\aSal
roSun4oSunr\oSunroUSVn
rOktoh4OktOroktorakt7N
sriSt`is4iStiSr\iS.tiSriSdi
ha~ShaS:hA:SpaS
tS_hatatSatatS)AtAtSada
dZOldZOldZ)AldZVl

For each stop and affricate in the sample, I then recorded which of the four categories it fell into, and how the volunteers identified it. The results are as follows.
Heard as
ActualPlainAspiratedVoicedVoiced aspiratedOther
Plain2711200
Aspirated132000
Voiced002010
Voiced aspirated32001

From this we can see that English speakers correctly identify plain stops as voiceless 70% of the time. They almost always identify voiceless stops as plain, whether or not they are aspirated. Aspirated voiceless stops are always identified as voiceless. Voiced stops are almost always correctly identified, and voiced aspirated stops, which are alien to English, are never correctly identified.

These results are more consistent with voicing being the primary feature than aspiration. Sorry, And.