Theoretical Grammar The subject-matter of theoretical grammar. Its relation to practical grammar

Unstressed vowels
In Early ME the pronunciation of unstressed syllables became increasingly indistinct. As compared to OE, which distinguishes five short vowels in unstressed position [e/i], [a] and [o/u], Late ME had only two vowels in unaccented syllables: [ə] and [i], e.g. OE talu – ME tale [΄ta:lə] – NE tale, OE bodiз – ME body [΄bodi] – NE body. The final [ə] disappeared in Late ME though it continued to be spelt as -e. When the ending –e survived only in spelling, it was understood as a means of showing the length of the vowel in the preceding syllable and was added to words which did not have this ending before, e.g. OE stān, rād – ME stone, rode [´stone], [´rode] – NE stone, rode. It should be remembered that while the OE unstressed vowels thus were reduced and lost, new unstressed vowels appeared in borrowed words or developed from stressed ones, as a result of various changes, e.g. the shifting of word stress in ME and NE, vocalization of [r] in such endings as writer, actor, where [er] and [or] became [ə].
Quantitative vowel changes in Early ME (see table)
In Later OE and in Early ME vowel length began to depend on phonetic conditions. The earliest of positional quantitative changes was the readjustment of quantity before some consonant clusters:
1) Short vowels were lengthened before two 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.
3) Short vowels became long in open syllables, e.g. OE nama > ME name [na:mə] – NE name. In spite of some restrictions no lengthening occurred in polysyllabic words and before some suffixes, OE bodiз > ME body [΄bodi] – NE body.