Complex sentence: Although it usually falls on the first syllable of a root, there are many words where it does not, mostly nouns, as well as a small class of common verbs whose stress may fall on a prefix rather than on the root.
Split into simpler sentences: Although it usually falls on the first syllable of a root, there are many words where it does not. These are mostly nouns, as well as a small class of common verbs whose stress may fall on a prefix rather than on the root.