Recently Adir and Alessandro made a podcast about pronunciation. They gave examples on inflection of the voice, sentence cadence, rythm, the rise and fall ofvoice pitch, and intonation. They explained the difference between languages that have stress timed rythm (like english) and syllable timed rythm (like Portuguese), and cautioned that if you do not pay attention to and adjust your rythm, your sentences may sound robotic when you speak.
This video demonstrates the importance of stress timed rythm because, being computer generated, it has none. Enjoy!