Perceiving Words, Phonemes, and Letters • 299One of the fascinating aspects of this effect is that if we were to analyze the sound
energy that occurs when people are having conversations, we might come to the opposite
conclusion—that it would be more diffi cult to perceive words when they are surrounded
by other words in a sentence. The reason we might think this is that words in conversa-
tions are not separated from one another by spaces, or pauses, even though it may sound
as though they are. We can see why this is so by remembering our discussion in Chapter 3,
in which we saw that a record of the physical energy produced by conversational speech
reveals either no physical breaks in the signal or breaks that don’t correspond to the
breaks we perceive between words (● Figure 11.2). The process of perceiving individual
words in the continuous fl ow of the speech signal is called speech segmentation.
Our ability to perceive individual words, even though there are often no pauses
between words in the sound signal, is aided by a number of factors. In Chapter 3 we
pointed out that when we listen to an unfamiliar foreign language, it is often diffi cult to
distinguish one word from the next, but if we know a language, individual words stand
out (see page 57). This observation illustrates that knowing the meanings of words
helps us perceive them. Perhaps you have had this experience, when words that you
happen to know in a foreign language seem to “pop out” from what appears to be an
otherwise continuous stream of speech.
Another example of how meaning is responsible for organizing sounds into words
is provided by these two sentences.Jamie’s mother said, “Be a big girl and eat your vegetables.”
The thing Big Earl loved most in the world was his car.“Big girl” and “Big Earl” are both pronounced the same way, so hearing them differ-
ently depends on the overall meaning of the sentence in which these words appear. This
example is similar to the familiar “I scream, you scream, we all scream for ice cream”
that many people learn as children. The sound stimuli for “I scream” and “ice cream”
are identical, so the different organizations must be achieved by the meaning of the
sentence in which these words appear.
Although segmentation is aided by knowing the meanings of words and being
aware of the context in which these words occur, listeners also use other information
to achieve segmentation. As we learn a language, we learn that certain sounds are more
likely to follow one another within a word, and other sounds are more likely to be sepa-
rated by the space between two words. For example, consider the words pretty baby. In
English it is more likely that pre and ty will follow each other in the same word (pre-ty)
and that ty and ba will be separated by a space so will be in two different words (pretty
baby). Thus, the space in the phrase prettybaby is most likely to be between pretty and●FIGURE 11.2 Sound energy for the phrase “Mice eat oats and does eat oats and little
lambs eat ivy.” The italicized words just below the sound record indicate how this phrase was
pronounced by the speaker. The vertical lines next to the words indicate where each word
begins. Note that it is diffi cult or impossible to tell from the sound record where one word
ends and the next begins. (Speech signal courtesy of Peter Howell.)meiz it oaz n doaz eet oaz n litl laamz eet ievee
mice
0 sec 0.5 1.0 1.5 2.0 2.5eat oats and does eat oats and little lambs eat ivy
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