The Probert Encyclopaedia of General Information

ACCENT

In English the term accent commonly denotes superior stress or force of voice upon certain syllables of words, which distinguishes them from the other syllables. Many English words, as aspiration have two accents, a secondary and primary, the latter being the fuller or stronger. Some words, as incomprehensibility/, have two secondary or subordinate accents. When the full accent falls on a vowel, that vowel has its long sound, as in vocal; but when it falls on a consonant, the preceding vowel is short, as in habit. This kind of accent alone regulates English verse as contrasted with Latin or Greek verse, in which the metre depended on quantity or length of syllables. In books on elocution three marks or accents are generally made use of, the first or acute ( / ) showing when the voice is to be raised, the second or grave ('), when it is to be depressed, and the third or circumflex (^) when the vowel is to be uttered with an undulating sound. In some languages there is no such distinct accent as in English (or German), and this seems to be now the case with French.
Research Accent