In disyllabic and trisyllabic compounds of nouns with certain prefixes, partly accented in Old English, as e.g. _al-_, _un-_, _for-_, _mis-_, _y-_, _a-_, _bi-_, the primary accent does not rest on these syllables, but on the second syllable, this being the root-syllable of the word, e.g. _almíhti_, _forgétful_, _unhéele_, _bihéeste_; the first syllable in this case bears a secondary accent if it has a determinative signification, as e.g. _al-_, _mis-_, _un-_, but it is unaccented if it is indifferent to the meaning, as e.g. _a-_, _y-_, _bi-_.
§ =116.= A peculiar rhythmical position is held by those words which we may call parathetic compounds.[141] To these belong certain compound nouns formed by two words of almost the same weight from a syntactical and metrical point of view, as e.g. _goodman_, _goodwyf_, _longswerd_, and also by similar composite particles, as e.g. _elleswhere_, _also_, _into_, _unto_. Although the regular colloquial pronunciation was probably in the Middle English period, as it is in Modern English, with the accent on the first syllable, they may be pronounced with the accent on the second syllable, or at least with level stress, as e.g. _g+oo+dm+á+n_, _+a+ls+ó+_, _+i+nt+ó+_, &c. To this class also belong certain compounds of adverbs with prepositions, as e.g. _herein_, _therefore_, _thereof_, the only difference being that the usual accent rests here on the last syllable, but may be placed also on the first, as in _hereín_ and _hérein_, _thereóf_ and _théreof_, &c.
§ =117.= These gradations of sound in the different words regulate their rhythmical treatment in the verse. In disyllabic words as a rule the syllable with the primary accent is placed in the arsis of the verse, the other syllable, whether it be an unaccented one, or have a secondary accent, is placed in the thesis. Such words as those described in the preceding section may much more easily be used with level stress than others. In that case the rhythmical accent rests on the syllable which has the secondary accent, while the syllable which in ordinary speech has the chief accent is used as a thesis.
The ordinary as well as the abnormal use of one and the same word will be illustrated by the following example:--