Short Paper 2: Lexical diffusion

Due session 12

Investigate a possible case of lexical diffusion or similar irregular sound change. Determine whether the sound change is in fact regular. If so, see if it is consistent with selected hypotheses about the properties of lexical diffusion. Write up your results as a short paper (about 1000 words).

Possible Topics

1. trap-bath split

A series of sound changes that have lead to some US English trap vowels corresponding to palm vowels in Southern British accents like RP, e.g. dance US [dæns] / RP [dɑːns], while other words have trap vowels in both accents, e.g. mass US/RP [mæs]. This looks like an irregular correspondence because it doesn’t seem to be predictable from phonological context whether a US trap vowel will correspond to trap or palm in RP English:

mass mæs mæs
pass pʰæs pʰɑːs
ant ænt ænt
grant ɡɹænt ɡɹɑːnt
asp æsp æsp
clasp kʰlæsp kʰlɑsp

Wells (1982) argues that these irregular correspondences are the result of a vowel lengthening change that was diffusing through the lexicon, but stopped before it affected all the words containing vowels in the relevant contexts. There are more data on this Wikipedia page and on this website at the British Library.

2. lot-cloth split

In US English, some Middle English short ‘o’ vowels have developed into the lot/palm vowel (e.g. [ɑ]), as in lot, while others have merged with the thought vowel [ɔ] (in dialects with a lot-thought contrast), as in cloth, but it does not seem to be entirely predictable which outcome you get in a given word. So the short ‘o’ phoneme has split, suggesting an irregular sound change. (Actually there is probably more than one change involved: short ‘o’ lengthened before voiceless fricatives in the 17th Century, and subsequently merged with long [ɔ] in US English). The unlengthened short ‘o’ vowels unrounded to [ɑ] in most of the US.

Earlier form  lɒt klɒθ
o lengthening - klɒːθ
THOUGHT merger - klɔθ
LOT unrounding lɑt -
Later form lɑt klɔθ

The ɒ > ɔ change seems to have applied more or less regularly before word-final fricatives, but seems to be irregular before medial fricatives (e.g. foster, but not roster), and has been extended in some dialects to apply before some voiced velar stops and nasals (dog, long), and a few alveolar nasals (usually just on, gone). So this change looks like a possible example of lexical diffusion.

There are more data on this Wikipedia page. (Don’t take it on trust—it’s Wikipedia—but it’s a good starting place).

It will be important to check etymologies of words—the sound change of interest involves Middle English short ‘o’ > [ɔ], but thought [ɔ] has many other sources. Spelling provides some indication of etymology, but it’s not a perfect guide.

3. foot-strut split

In the early 17th Century, Middle English short [ʊ] unrounded to [ʌ] (strut) in words like cut, but not in words like put (foot words). (The change presumably involved intermediate steps, e.g. ʊ > ɤ > ʌ). Preceding labials tended to block unrounding (as in put, full), but incidence of the change is apparently not predictable (e.g. putt, fun are strut words in spite of beginning with labials). So the ʊ > ʌ change is a candidate for a change that was diffusing through the lexicon, but was never completed.

The main focus should be on strut words, since they mostly come from short [ʊ] by unrounding, whereas foot words can also come from later shortening of long [u], as in good, making it hard to tell which foot vowels are the result of blocked unrounding. (This u-shortening is also an irregular change—see below). Look for exceptions to the generalization that the strut vowel should not follow labials, and see if they follow any more specific generalizations, or if the change was truly irregular.

4. Later /uː/ shortening

After the foot-strut split, long [uː] shortened to [ʊ] (foot) in certain contexts. This shortening was quite consistent in some contexts, but appears to be irregular in others, and is still variable now (e.g. room [ɹuːm/ɹʊm], roof [ɹuːf/ɹʊf]).

5. trap tensing before sT in Long Island

In Long Island English, trap [æ] tenses before word-medial [st, sk, sp] clusters in some words, but not all, e.g. master [mɛːstə˞], but asterisk [æstəɹɪsk]. What determines which words of this type undergo tensing? I have some data and can collect more from the speaker you studied in paper 1.

6. ‘Milk-to-melk’

…or other word-specific changes represented in your speech (or your friends’ speech). In class we have heard about some apparently irregular changes that show up in your speech, e.g. kit [ɪ] > dress [ɛ] in words like milk, pillow, vanilla. Investigating a change like this is a bit different because the change may only affect a few words, so it may be harder to nail down what is going on, but it should still be possible to address interesting questions, and generate hypotheses for further investigation.

Things to address:

Check whether the sound change you are investigating is actually irregular.

  • Examine the data. Although they are all reported to be irregular, perhaps people have missed some phonological factors that differentiate the words that undergo the change from those that do not. Or there could be morphological factors that condition the change.
  • If there are still irregularities, try to check whether the exceptions could be later loanwords borrowed after a regular change had been completed and was no longer phonologically active. Dates of first known uses of words are available in the Oxford English Dictionary (see resources below).
  • What are the contexts in which the change tends to occur? Are there contexts where it applies regularly?
  • If your change is not irregular, you’re done! Write up the argument that the change is actually regular.

Assuming your sound change is irregular, try to test some hypotheses concerning the nature of lexical diffusion:

  • Lexical diffusion involves substitution of one pre-existing phoneme for another in the underlying representations of individual words (Labov 1981). Is there evidence that the sounds involved in the change were contrastive phonemes before the change began? If there isn’t good evidence that the sounds are distinct phonemes, are they at least involved in surface contrasts? E.g. like the [bænə˞] ‘flag’ vs. [beænə˞] ‘one who bans’ contrasts observed in trap-tensing dialects.
  • Lexically diffusing sound changes target higher frequency words first (Phillips 2006, Pierrehumbert 2001). (See ‘Resources’ for a source of word frequency data).
  • The examples of lexical diffusion that we have seen seem to involve extension of a regular sound change to new environments. Is that the case for your change? I.e. is there a core set of environments where the change has applied regularly, then a set of (related) environments in which the change is irregular?
  • Phoneme substitution changes tend to apply in contexts where the phonemes sound similar (e.g. due to assimilation to context, coarticulatory effects etc). Investigating this hypothesis is likely to involve making and analyzing recordings.
  • Phoneme substitution changes are more likely to apply to a word if the change does not make it identical to a pre-existing word (Bertics, p.c.). E.g. milk can change to [mɛlk] because that was not already a word. Ilk is less likely to change to [ɛlk] because that is already a word.

In general, see if you can work out what factors affect which words undergo the change. Not all of these hypotheses will be equally relevant to all sound changes—focus on those that your data bear on.

General resources

For each sound change, I have some short readings and lists of relevant words, mostly from Wells (1982). Contact me, and I’ll send you what I have.


The OED records UK and US pronunciations. The UK pronunciations are mostly RP English (e.g. they show the trap-bath split). The US pronunciations include those exemplifying the lot-cloth split. The American Heritage Dictionary reports US pronunciation.

Both also contain information about etymology in case you need to find out whether a word really descends from a Middle English word with short ‘o’ (for example). The OED etymological information is more detailed, but the detail can be hard to work through sometimes.

The OED also contains dates of first recorded uses of words.

Word frequency information

Use the spoken part of the American National Corpus.

Recordings and acoustic analysis—talk to me if you’d like help making a recording in phonetics lab.