Accent and pitch (which plays an important part in intonation) render your speech rhythmical and make it alive. You cannot express your feelings exactly without them.
The loudness and highness (and lowness) of voice vary according to the degree of tension of the pharyngo-esophagus and the diaphragm (or the abdomen).
Stress
In some words, the syllable to be accented determines the meaning. For example, IN-crease is a noun, in-CREASE, a verb (the stressed syllables are written in capital letters). Let's try PRO-ject, pro:JECT; SUB-ject, sub-JECT; PRE-sent, pre-SENT; PRO-duce, pro-DUCE IM port, im-PORT.
