Name: 語音發展 (Phonological development)
Uploaded: 2021-01-14T06:28:44.000Z
Duration: 24 min 3 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Sound is at the beginning of language learning. Children have to learn to

distinguish different sounds and to segment the speech stream they are

exposed to into units – eventually meaningful units – in order to acquire

words and sentences. Here is one reason that speech segmentation is challenging:

When you read, there are spaces between the words. No such spaces occur between

spoken words. So, if an infant hears the sound sequence “thisisacup,” it has to

learn to segment this stream into the distinct units “this”, “is”, “a”, and

“cup.” Once the child is able to extract the sequence “cup” from the speech

stream it has to assign a meaning to this word. Furthermore, the child has to

be able to distinguish the sequence “cup” from “cub” in order to learn that

these are two distinct words with different meanings. Finally, the child

has to learn to produce these words. The acquisition of native language phonology

begins in the womb and isn’t completely adult-like until the teenage years.

Perceptual abilities usually precede production and thus aid the development

of speech production. Prelinguistic development

= Perception = Children don’t utter their first words

until they are about 1 year old, but already at birth they can tell some

utterances in their native language from utterances in languages with different

= Categorical perception = Infants as young as 1 month perceive

some speech sounds as speech categories. For example, the sounds  and  differ in

the amount of breathiness that follows the opening of the lips. Using a

computer generated continuum in breathiness between  and , Eimas et al.

showed that English-learning infants paid more attention to differences near

the boundary between  and  than to equal-sized differences within the

-category or within the -category. Their measure, monitoring infant sucking-rate,

became a major experimental method for studying infant speech perception.

Infants up to 10–12 months can distinguish not only native sounds but

also nonnative contrasts. Older children and adults lose the ability to

discriminate some nonnative contrasts. Thus, it seems that exposure to one’s

native language causes the perceptual system to be restructured. The

restructuring reflects the system of contrasts in the native language.

4 months  At four months infants still prefer

infant-directed speech to adult-directed speech. Whereas 1-month-olds only

exhibit this preference if the full speech signal is played to them,

4-month-old infants prefer infant-directed speech even when just

the pitch contours are played. This shows that between 1 and 4 months of

age, infants improve in tracking the suprasegmental information in the speech

directed at them. By 4 months, finally, infants have learned which features they

have to pay attention to at the suprasegmental level.

5 months  Babies prefer to hear their own name to

similar sounding words. It is possible that they have associated the meaning

“me” with their name, although it is also possible that they simply recognize

the form because of its high frequency. 6 months

With increasing exposure to the ambient language, infants learn not to pay

attention to sound distinctions that are not meaningful in their native language,

e.g., two acoustically different versions of the vowel  that simply

differ because of inter-speaker variability. By 6 months of age infants

have learned to treat acoustically different sounds that are

representations of the same sound category, such as an  spoken by a male

versus a female speaker, as members of the same phonological category .

= Statistical learning = Infants are able to extract meaningful

distinctions in the language they are exposed to from statistical properties

of that language. For example, if English-learning infants are exposed to

a prevoiced  to voiceless unaspirated  continuum with the majority of the

tokens occurring near the endpoints of the continuum, i.e., showing extreme

prevoicing versus long voice onset times they are better at discriminating these

sounds than infants who are exposed primarily to tokens from the center of

the continuum. These results show that at the age of 6

months infants are sensitive to how often certain sounds occur in the

language they are exposed to and they can learn which cues are important to

pay attention to from these differences in frequency of occurrence. In natural

language exposure this means typical sounds in a language occur often and

infants can learn them from mere exposure to them in the speech they

hear. All of this occurs before infants are aware of the meaning of any of the

words they are exposed to, and therefore the phenomenon of statistical learning

has been used to argue for the fact that infants can learn sound contrasts

without meaning being attached to them. At 6 months, infants are also able to

make use of prosodic features of the ambient language to break the speech

stream they are exposed to into meaningful units, e.g., they are better

able to distinguish sounds that occur in stressed vs. unstressed syllables. This

means that at 6 months infants have some knowledge of the stress patterns in the

speech they are exposed and they have learned that these patterns are

At 7.5 months English-learning infants have been shown to be able to segment

words from speech that show a strong-weak stress pattern, which is the

most common stress pattern in the English language, but they were not able

to segment out words that follow a weak-strong pattern. In the sequence

‘guitar is’ these infants thus heard ‘taris’ as the word-unit because it

follows a strong-weak pattern. The process that allows infants to use

prosodic cues in speech input to learn about language structure has been termed

While children generally don’t understand the meaning of most single

words yet, they understand the meaning of certain phrases they hear a lot, such

as “Stop it,” or “Come here.” 9 months

Infants can distinguish native from nonnative language input using phonetic

and phonotactic patterns alone, i.e., without the help of prosodic cues. They

seem to have learned their native language’s phonotactics, i.e., which

combinations of sounds are possible in the language.

10-12 months  Infants now can no longer discriminate

most nonnative sound contrasts that fall within the same sound category in their

native language. Their perceptual system has been tuned to the contrasts relevant

in their native language. As for word comprehension, Fenson et al. tested

10-11-month-old children’s comprehension vocabulary size and found a range from

11 words to 154 words. At this age, children normally have not yet begun to

speak and thus have no production vocabulary. So clearly, comprehension

vocabulary develops before production vocabulary.

= Production = Stages of pre-speech vocal development

Even though children do not produce their first words until they are

approximately 12 months old, the ability to produce speech sounds starts to