Editing Trisyllabic laxing (section)

==Trisyllabic laxing==
Trisyllabic laxing is a process which has occurred at various periods in the history of English:
#The earliest occurrence of trisyllabic laxing occurred in late [[Old English]] and caused stressed [[long vowel]]s to become shortened before clusters of two consonants when two or more syllables followed.
#Later in [[Middle English]], the process was expanded to all vowels when two or more syllables followed.
#The Middle English sound change remained in the language and is still a mostly-productive process in [[Modern English]], detailed in Chomsky and Halle's ''[[The Sound Pattern of English]]''.

The Middle English sound change occurred before the [[Great Vowel Shift]] and other changes to the nature of vowels. As a result of the changes, the pairs of vowels related by trisyllabic laxing often bear little resemblance to one another in Modern English; however, originally they always bore a consistent relationship. For example, tense {{IPA|/aʊ/}} was {{IPA|[uː]}}, and lax {{IPA|/ʌ/}} was {{IPA|[u]}} at the time of trisyllabic laxing.

In some cases, trisyllabic laxing appears to take place when it should not have done so: for example, in "south" {{IPAc-en|'|s|aʊ|θ}} vs. "southern" {{IPAc-en|ˈ|s|ʌ|ð|ər|n}}. In such cases, the apparent anomaly is caused by later sound changes: "southern" (formerly ''southerne'') was pronounced {{IPA|/suːðernə/}} when trisyllabic laxing applied.

In the modern English language, there are systematic exceptions to the process, such as in words ending in ''-ness'': "mindfulness, loneliness". There are also occasional, non-systematic exceptions such as "obese, obesity" ({{IPAc-en|oʊ|ˈ|b|iː|s|ɪ|t|i}}, not *{{IPAc-en|oʊ|ˈ|b|ɛ|s|ɪ|t|i}}), although in this case the former was back-formed from the latter in the 19th century.

{| class=wikitable
! Tense <br>vowel
! →
! Lax <br>vowel
! Change in <br>[[Middle English]]
! Example
! IPA
|-
| {{IPA|iː}}
| →
| {{IPA|ɛ}}
| {{IPA|eː → e}}<br>{{IPA|ɛː → e}}
| ser'''e'''ne, ser'''e'''nity;
imp'''e'''de, imp'''e'''diment
| {{IPA|/sᵻˈr'''iː'''n, sᵻˈr'''ɛ'''nᵻti/}};
{{IPA|/ɪmˈp'''iː'''d, ɪmˈp'''ɛ'''dᵻmənt/}}
|-
| {{IPA|eɪ}}
| →
| {{IPA|æ}}
| {{IPA|aː → a}}
| prof'''a'''ne, prof'''a'''nity;
gr'''a'''teful, gr'''a'''titude
|{{IPA|/prəˈf'''eɪ'''n, prəˈf'''æ'''nᵻti/}}
{{IPA|/ˈɡr'''eɪ'''tfəl, ˈɡr'''æ'''tᵻtjuːd/}}
|-
| {{IPA|aɪ}}
| →
| {{IPA|ɪ}}
| {{IPA|iː → i}}
| div'''i'''ne, div'''i'''nity;
der'''i'''ve, der'''i'''vative
| {{IPA|/dᵻˈv'''aɪ'''n, dᵻˈv'''ɪ'''nᵻti/}};
{{IPA|/dᵻˈr'''aɪ'''v, dᵻˈr'''ɪ'''vətᵻv/}}
|-
| {{IPA|aʊ}}
| →
| {{IPA|ʌ}}
| {{IPA|uː → u}}
| prof'''ou'''nd, prof'''u'''ndity;
pron'''ou'''nce, pron'''u'''nciation;
| {{IPA|/prəˈf'''aʊ'''nd, prəˈf'''ʌ'''ndᵻti/}};
{{IPA|/prəˈn'''aʊ'''ns, prəˌn'''ʌ'''nsiˈeɪʃən/}}
|-
| {{IPA|uː}}
| →
| {{IPA|ɒ}}
| {{IPA|oː → o}}
| colspan=2|(No longer part of the active vowel system of English)<ref>April McMahon (2000) ''Lexical Phonology and the History of English'', p. 112</ref> 
|-
| {{IPA|oʊ}}
| →
| {{IPA|ɒ}}
| {{IPA|ɔː → o}}
| prov'''o'''ke, prov'''o'''cative; 
s'''o'''le, s'''o'''litude
| {{IPA|/prəˈv'''oʊ'''k, prəˈv'''ɒ'''k.ə.tɪv/}};
{{IPA|/ˈs'''oʊ'''l, ˈs'''ɒ'''lᵻtjuːd/}}
|}