§ 7. SOUND CHANGES. (_a_) #Vowel Quantity.# No fourteenth-century writer followed the early example of Orm. Marks of quantity are not used in fourteenth-century texts; doubling of long vowels is not an established rule; and there are no strictly quantitative metres, or treatises on pronunciation. Consequently it is not easy to determine how far the quantity of the vowels in any given text has been affected by the very considerable changes that occurred in the late OE. and ME. periods. Of these the chief are: (i) In unstressed syllables original long vowels tend to become short. Hence _ŭs_ (OE. _ūs_), and _bŏte_ (OE. _būtan_) 'but', which are usually unstressed. (ii) All long vowels are shortened in stressed close syllables (i.e., _usually_, when they are followed by two consonants): e.g. _kēpen_, pa. t. _kĕpte_, pp. _kĕpt_; _hŭsband_ beside _hous_; _wĭmmen_ (from _wĭf-men_) beside _wīf_. _Exception._ Before the groups _-ld_, _-nd_, _-rd_, _-rð_, _-mb_, a short vowel is lengthened in OE. unless a third consonant immediately follows. Hence, before any of these combinations, length may be retained in ME.: e.g. _fēnd_ 'fiend', _bīnden_, _chīld_; but _chĭldren_. (iii) Short vowels _ă_, _ĕ_, _ŏ_ are lengthened in stressed open syllables (i.e., _usually_, when they are followed by a single consonant with a following vowel): _tă|ke_ > _táke_; _mĕ|te_ > _méte_ 'meat'; _brŏ|ken_ > _bróken_. To what extent _ĭ_ and _ŭ_ were subject to the same lengthening in Northern districts is still disputed. Normally they remain short in South and S. Midlands, e.g. _drĭuen_ pp.; _lŏuen_ = _lŭven_ 'to love'. There are many minor rules and many exceptions due to analogy; but roughly it may be taken that ME. vowels are: _short_ when unstressed; _short_ before two consonants, except _-ld_, _-nd_, _-rd_, _-rð_, _-mb_; _long_ (except _i_ (_y_), _u_) before a single medial consonant; otherwise of the quantity shown in the Glossary for the OE. or ON. etymon. (_b_) #Vowel Quality.# The ME. sound-changes are so many and so obscure that it will be possible to deal only with a few that contribute most to the diversity of dialects, and it happens that the particular changes noticed all took effect before the fourteenth century. (i) OE. and ON. _ā_ develop to long open _ǭ_ (sounded as in _broad_), first in the South and S. Midlands, later in the N. Midlands. In the North _ā_ (sounded approximately as in _f~a~ther_) remains: e.g. _bane_ 'bone' IV _a_ 54, _balde_ 'bold' IV _a_ 51. The boundary seems to have been a line drawn west from the Humber, and this approximates to the dividing line in the modern dialects. There are of course instances of _ǭ_ to the north and of _ā_ to the south of the Humber, since border speakers would be familiar with both _ā_ and _ǭ_, or would have intermediate pronunciations; and poets might use convenient rimes from neighbouring dialects.