Stress is understood as syllable prominence or emphasis on a certain part of a word or a sentence that can be associated with greater loudness (intensity), pitch (frequency), length (duration).

There are two patterns of stress: word stress and sentence stress.

Functions of Word Stress

The role of word stress in intelligible communication is apparent and acknowledged by many. It is a suprasegmental that gives the overall shape to words. Thus, the word pronounced with inappropriate accentual pattern may not be understood. For example, vocabulary [vₔ'kᴂbjulₔri] may be unintelligible as being distorted as [vokₔ'bjulari]. Word stress gives a listener clue to the word’s profile even that only the first syllables of the word are pronounced. “Photograph” and “photographer” are the good illustration in this case. Even when hearing the first two syllables “photo”, with word stress, listeners can immediately recognize whether it is “photograph” and “photographer” because the former is stressed on the first syllable “PHOto” and the latter’s stress is on the second “phoTO” (Cornelius, 2009, p.36)

Functions of Sentence Stress

1. Distinguishing new and old information

In the following dialogue between A and B, when B introduces new information to the discourse context, it receives primary stress (indicated by ´), while lexical items that represent old information are unstressed (indicated by the bolded word):

A: Are you ready?

B: I’m álways ready. (Hahn, 2004)

2. Marking contrast

In the following example, the speaker makes a comparison between the two kinds of wine, so though “prefer” and “wine” are content words, “red” and “white” are stressed the most in the utterance.

I prefer réd wine to whíte wine.

 

Reference

Cornelius, C. Y. (2009). Phonetics and phonology of English II. Center of San Marcos University Press. Retrieved on January 20^th, 2016 from www.scribd.com/doc/70131754/16/Prosodic-features-Intonation-stress-tone-pitch-and-length

Hahn, L. D. (2004). Primary stress and intelligibility: Research to motivate the teaching of suprasegmentals. TESOL Quarterly 38. 201-223.