If the word consists of three or more syllables there is usually another syllable stressed in somewhat less degree.

This is called a secondary accent.

In some cases there may even be a third accent if the word is very long; _In'-come_, _val-e-tu'-di-na'-ri-an_.

This fact arises from the tendency natural to all human speech to take more or less musical forms.

The monotony of a series of stressed or of unstressed sounds would be unbearable.