III Stress Shifts
Not only vowels and consonants have changed over the centuries. Also the stress of words has changed.
Fluctuation of stress is typical for the Early Modern period. This is partly a consequence of a conflict between the native system of accentuation, "in which the stress was normally on the stem” (Barber 1976, 323), and the French and Latin mode of accentuation in loanwords. Charles Butler’s English Grammar attempts at giving rules for the accentuation of English. According to Butler most words are stressed just like in Present Day English.
French or Latin loanwords, however, are exceptional because especially polysyllabic words are stressed on the first syllable as in acceptable, commune, confesso, etc. (Cf. Barber 1976, 323). Butler shows second-syllable stress in words like confiscate and turmoil, whereas for instance reconcile is stressed on the third syllable. (Ibid)
In ME, many words also had a syllable that carried secondary stress. (Cf. Barber 1976, 324) In late ME there also arose variants with single stressing. Consequently, in the 16th century both types existed in the English language. In the course of the 17th century words with one main stress were the norm in informal speech.
Still, some of those with secondary stress survived, though mainly in formal and “careful speech” (Barber 1976, 324). Forms with secondary stress continued to be used in poetry and traditional literary forms.
It is not easy to be definite about word stress in this period as there was an unusual amount of variation. Stress varied depending on the position in which a word appeared in a sentence or metrical line. (Cf. Crystal 2003, 69)