§ 370. At the end of OE and in the immediately succeeding centuries accented vowels underwent a number of quantitative changes which affected the employment and the phonological status of short and long vowels in the language. It should be recalled that in OE quantity was the main basis of correlation in the vowel system; short vowels were phonemically opposed to long ones, roughly identical in quality. At that time vowel length was for the most part an inherited feature: OE short vowels had developed from PG short vowels, while long ones went back to long vowels or bi-phonemic vowel sequences (except for a few lengthenings, mainly due to the loss of consonants, see § 143, 144).
In later OE and in Early ME vowel length began to depend on phonetic conditions.
§371. The earliest of positional quantitative changes was the readjustment of quantity before some consonant clusters; it occurred in Early ME or perhaps even in Late OE.
(1) Short vowels were lengthened before two homorganic consonants, a sonorant and a plosive; consequently, all vowels occurring in this position remained or became long, e.g. OE wild > ME wild [wi:ld] (NE wild);
(2)All other groups of two or more consonants produced the reverse effect: they made the preceding long vowels short, and henceforth all vowels in this position became or remained short, e.g. OE cēpte > ME kepte ['keptə] (NE kept); OE bewildrian > ME bewildren [be'wildrən] (NE bewilder). (Cf. the latter example with wild given above; the third consonant [r] in ME bewildren prevented the lengthening.)
§ 372. Another decisive alteration in the treatment of vowel quantity took place some time later: in the 12th or 13th c.
(3) Short vowels became long in open syllables. This lengthening mainly affected the more open of the short vowels [e], [a] and [o], but sometimes, though very seldom, it is also found in the close vowels, [i]and [u]. In the process of lengthening close vowels acquired a more open quality, e.g..
|OE||open >||ME||open||['ɔ:pən]||(NE open)|
|wike >||weke||['we:kə]||(NE week)|
|nama >||name||['na:mə]||(NE name)|
In spite of some restrictions (e.g. no lengthening occurred in polysyllabic words and before some suffixes, OE bodiʒ > ME body ['bodi] (NE body), the alteration affected many words (see Table 1 on p. 194).
§ 373. The changes of vowel quantity reduced the number of positions in which the opposition of long vowels to short ones could be used for phonemic contrast. Before a consonant cluster vowel quantity was now predetermined by the nature of the cluster; and in open syllables three vowels - [ɔ], [a:] and [ɛ:] were always long. Consequently, opposition through quantity could be used for distinction, as a phonological feature, only in the absence of those phonetic conditions, namely: in closed syllables, in polysyllabic words, or with the vowels [i] and [u] in open syllables. Such is the contrast, e.g. in ME risen ['ri:zən] inf. and risen ['rizən] Part. II (NE rise, risen). The limitations in the application of vowel length as a distinctive feature undermined the role of vowel quantity in the language.
§ 374. Quantitative vowel changes in Early ME have given rise to a number of explanations and hypotheses.
AH the changes in vowel quantity have been interpreted as manifestations of a sort of rhythmic tendency. In order to achieve an average uniformity in the length of the syllable, and also to use an average amount of energy for its pronunciation, the vowel was shortened before a group of consonants and was made longer if there were no consonants following, that is, in "open" syllables. Lengthening of vowels before homorganic groups looks as an exception or a contradiction; to account for this lengthening it was suggested that -nd, -ld and the like were virtually equivalent to single consonants, therefore a long vowel would not make the syllable too heavy.
Quantitative Vowel Changes in Late Old English and Early Middle English
|Phonetic conditions||Change illustrated||Examples|
|Before homorganic consonant sequences: sonorant plus plosive (ld, nd, mb)||Vowels become long||cild findan climban cold feld fundon gold||child [tʃi:ld] finden [fi:ndən] climben ['kli:mbən] cold ['ko:ld] field [fe:ld] founden ['fu:ndən] gold [go:ld]||child find climb cold field found (Past of find) gold|
|Before other consonant sequences||Vowels become short||fiftiʒ fēdde mētte wisdōm||fifty [fifti] fedde ['feddə] mette ['mettə] wisdom ['wizdəm]||fifty fed met wisdom|
|In open syllables||Vowels become long and more open||mete stelan macian talu nosu stolen yfel duru||mete ['mɛ:tə] stelen ['stɛ:lən] maken ['ma:kən] tale ['ta:lə] nose ['nɔ:zə] stolen ['stɔ:lən] yvel, evel [i:], [e:] doore ['do:rə]||meat steal make tale nose stolen evil door|
This theory was criticised for attributing all the quantitative changes to one general cause - the effort to maintain a uniform syllable length - though in reality the changes were not simultaneous. Lengthening in open syllables occurred at a later period - some time in the 13th c. - and may have been caused by other factors. To cope with this difficulty, it was suggested that lengthening in open syllables was tied up with the weakening of final vowels; when the second, unaccented, syllable was weakened, the first syllable became more prominent and the vowel was made longer. Cf. OE talu and ME tale ['ta:lə] - the average amount of energy required for the pronunciation of the word is the same but its distribution is different.