Speech acquisition

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Speech acquisition focuses on the development of vocal, acoustic and oral language by a child. This includes motor planning and execution, pronunciation, phonological and articulation patterns (as opposed to content and grammar which is language).

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Spoken speech consists of an organized set of sounds or phonemes that are used to convey meaning while language is an arbitrary association of symbols used according to prescribed rules to convey meaning. [1] While grammatical and syntactic learning can be seen as a part of language acquisition, speech acquisition includes the development of speech perception and speech production over the first years of a child's lifetime. There are several models to explain the norms of speech sound or phoneme acquisition in children.

Development of speech perception

Sensory learning concerning acoustic speech signals already starts during pregnancy. Hepper and Shahidullah (1992) described the progression of fetal response to different pure tone frequencies. They suggested fetuses respond to 500 Hertz (Hz) at 19 weeks gestation, 250 Hz and 500 Hz at 27 weeks gestation and finally respond to 250, 500, 1000, 3000 Hz between 33 and 35 weeks gestation. [2] Lanky and Williams (2005) [3] suggested that fetuses could respond to pure tone stimuli of 500 Hz as early as 16 weeks.

The newborn is already capable of discerning many phonetic contrasts. This capability may be innate. Speech perception becomes language-specific for vowels at around 6 months, for sound combinations at around 9 months and for language-specific consonants at around 11 months. [4]

Infants detect typical word stress patterns, and use stress to identify words around the age of 8 months. [4]

As an infant grows into a child their ability to discriminate between speech sounds should increase. Rvachew (2007) [5] described three developmental stages in which a child recognizes or discerns adult-like, phonological and articulatory representations of sounds. In the first stage, the child is generally unaware of phonological contrast and can produce sounds that are acoustically and perceptually similar. In the second stage the child is aware of phonological contrasts and can produce acoustically different variations imperceptible to adult listeners. Finally, in the third stage, children become aware of phonological contrasts and produce different sounds that are perceptually and acoustically accurate to an adult production.

It is suggested that a child's perceptual capabilities continue to develop for many years. Hazan and Barrett (2000) [6] suggest that this development can cotton into late childhood; 6- to 12-year-old children showed increasing mastery of discriminating synthesized differences in place, manner, and voicing of speech sounds without yet achieving adult-like accuracy in their own production.

Typologies of infant vocalization

Infants are born with the ability to vocalize, most notably through crying. As they grow and develop, infants add more sounds to their inventory. There are two primary typologies of infant vocalizations. Typology 1: Stark Assessment of Early Vocal Development [7] consists of 5 phases.

  1. Reflexive (0 to 2 months of age) consisting of crying, fussing, and vegetative sounds
  2. Control of phonation (1 to 4 months of age) consonant-like sounds, clicks, and raspberry sound
  3. Expansion (3 to 8 months of age) isolated vowels, two or more vowels in a row, and squeals
  4. Basic canonical syllables (5 to 10 months of age) – a consonant vowel (CV) combination, often repeated (e.g. ba ba ba ba).
  5. Advanced forms (9 to 18 months of age) complex combinations of differing constant-vowel combinations (CVC) and jargon.

Typology 2: Oller's typology of infant phonations [8] consists primarily of 2 phases with several substages. The 2 primary phases include Non-speech-like vocalizations and Speech-like vocalizations. Non-speech-like vocalizations include a. vegetative sounds such as burping and b. fixed vocal signals like crying or laughing. Speech-like vocalizations consist of a. quasi-vowels, b. primitive articulation, c. expansion stage and d. canonical babbling.

Speech sound normative data

Knowing when a speech sound should be accurately produced helps parents and professionals determine when child may have an articulation disorder. There have been two traditional methods used to compare a child's articulation of speech sounds to chronological age. The first is comparing the number of correct responses on a standardized articulation test with the normative data for a given age on the same test. This allows evaluators to see how well a child is producing sounds compared to their same aged peers. The second method consists of comparing an individual sound a child produces with developmental norms for that individual sound. The second method can be difficult when considering the differing normative data and other factors that affect typical speech development. Many norms are based on age expectations in which a majority of children of a certain age are accurately producing a sound (75% or 90% depending on the study). Using the results from Sander (1972), [9] Templin (1957), [10] and Wellman, Case, Mengert, & Bradbury, (1931), [11] the American Speech-Language Hearing Association suggests the following: Sounds mastered by age 3 include /p, m, h, n, w, b/; by age 4 /k, g, d, f, y/; by age 6 /t, ŋ, r, l/; by age 7 /tʃ, ʃ, j, θ/. and by age 8 /s, z, v, ð, ʒ/. [12]

Early, Middle, and Late 8s

Shriberg (1993) [13] proposed a model for speech sound acquisition known as the Early, Middle, and Late 8 based on 64 children with speech delays ages 3 to 6 years. Shriberg proposed that there were three stages of phoneme development. Using a profile of "consonant mastery" he developed the following:

See also

Related Research Articles

Phonetics is a branch of linguistics that studies how humans produce and perceive sounds, or in the case of sign languages, the equivalent aspects of sign. Linguists who specialize in studying the physical properties of speech are phoneticians. The field of phonetics is traditionally divided into three sub-disciplines based on the research questions involved such as how humans plan and execute movements to produce speech, how various movements affect the properties of the resulting sound, or how humans convert sound waves to linguistic information. Traditionally, the minimal linguistic unit of phonetics is the phone—a speech sound in a language which differs from the phonological unit of phoneme; the phoneme is an abstract categorization of phones, and it is also defined as the smallest unit that discerns meaning between sounds in any given language.

Fis phenomenon is a phenomenon during a child's language acquisition that demonstrates that perception of phonemes occurs earlier than a child's ability to produce the appropriate allophone. It is also illustrative of a larger theme in child language acquisition: that skills in linguistic comprehension generally precede corresponding skills in linguistic production. The name comes from an incident reported in 1960 by J. Berko and R. Brown, in which a child referred to his inflatable plastic fish as a fis. However, when adults asked him, "Is this your fis?" he rejected the statement. When he was asked, "Is this your fish?" he responded, "Yes, my fis." This shows that although the child could not produce the phoneme /ʃ/, he could perceive it as being different from the phoneme /s/. In some cases, the sounds produced by the child are actually acoustically different, but not significantly enough for others to distinguish since the language in question does not make such contrasts.

Lip reading, also known as speechreading, is a technique of understanding speech by visually interpreting the movements of the lips, face and tongue when normal sound is not available. It relies also on information provided by the context, knowledge of the language, and any residual hearing. Although lip reading is used most extensively by deaf and hard-of-hearing people, most people with normal hearing process some speech information from sight of the moving mouth.

<span class="mw-page-title-main">Babbling</span> Stage in child development and language acquisition

Babbling is a stage in child development and a state in language acquisition during which an infant appears to be experimenting with uttering articulate sounds, but does not yet produce any recognizable words. Babbling begins shortly after birth and progresses through several stages as the infant's repertoire of sounds expands and vocalizations become more speech-like. Infants typically begin to produce recognizable words when they are around 12 months of age, though babbling may continue for some time afterward.

Baby talk is a type of speech associated with an older person speaking to a child or infant. It is also called caretaker speech, infant-directed speech (IDS), child-directed speech (CDS), child-directed language (CDL), caregiver register, parentese, or motherese.

Speech delay, also known as alalia, refers to a delay in the development or use of the mechanisms that produce speech. Speech – as distinct from language – is the actual process of making sounds, using such organs and structures as the lungs, vocal cords, mouth, tongue, teeth, etc. Language delay refers to a delay in the development or use of the knowledge of language.

Language development in humans is a process starting early in life. Infants start without knowing a language, yet by 10 months, babies can distinguish speech sounds and engage in babbling. Some research has shown that the earliest learning begins in utero when the fetus starts to recognize the sounds and speech patterns of its mother's voice and differentiate them from other sounds after birth.

In speech communication, intelligibility is a measure of how comprehensible speech is in given conditions. Intelligibility is affected by the level and quality of the speech signal, the type and level of background noise, reverberation, and, for speech over communication devices, the properties of the communication system. A common standard measurement for the quality of the intelligibility of speech is the Speech Transmission Index (STI). The concept of speech intelligibility is relevant to several fields, including phonetics, human factors, acoustical engineering, and audiometry.

<span class="mw-page-title-main">Speech</span> Human vocal communication using spoken language

Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words, and using those words in their semantic character as words in the lexicon of a language according to the syntactic constraints that govern lexical words' function in a sentence. In speaking, speakers perform many different intentional speech acts, e.g., informing, declaring, asking, persuading, directing, and can use enunciation, intonation, degrees of loudness, tempo, and other non-representational or paralinguistic aspects of vocalization to convey meaning. In their speech, speakers also unintentionally communicate many aspects of their social position such as sex, age, place of origin, physical states, psychological states, physico-psychological states, education or experience, and the like.

Speech perception is the process by which the sounds of language are heard, interpreted, and understood. The study of speech perception is closely linked to the fields of phonology and phonetics in linguistics and cognitive psychology and perception in psychology. Research in speech perception seeks to understand how human listeners recognize speech sounds and use this information to understand spoken language. Speech perception research has applications in building computer systems that can recognize speech, in improving speech recognition for hearing- and language-impaired listeners, and in foreign-language teaching.

Developmental linguistics is the study of the development of linguistic ability in an individual, particularly the acquisition of language in childhood. It involves research into the different stages in language acquisition, language retention, and language loss in both first and second languages, in addition to the area of bilingualism. Before infants can speak, the neural circuits in their brains are constantly being influenced by exposure to language. Developmental linguistics supports the idea that linguistic analysis is not timeless, as claimed in other approaches, but time-sensitive, and is not autonomous – social-communicative as well as bio-neurological aspects have to be taken into account in determining the causes of linguistic developments.

A speech sound disorder (SSD) is a speech disorder in which some sounds (phonemes) are not produced or used correctly. The term "protracted phonological development" is sometimes preferred when describing children's speech, to emphasize the continuing development while acknowledging the delay.

Speech production is the process by which thoughts are translated into speech. This includes the selection of words, the organization of relevant grammatical forms, and then the articulation of the resulting sounds by the motor system using the vocal apparatus. Speech production can be spontaneous such as when a person creates the words of a conversation, reactive such as when they name a picture or read aloud a written word, or imitative, such as in speech repetition. Speech production is not the same as language production since language can also be produced manually by signs.

Phonological development refers to how children learn to organize sounds into meaning or language (phonology) during their stages of growth.

In phonology and historical linguistics, cluster reduction is the simplification of consonant clusters in certain environments or over time. Cluster reduction can happen in different languages, dialects of those languages, in world Englishes, and as a part of language acquisition.

<span class="mw-page-title-main">Speech repetition</span> Repeating something someone else said

Speech repetition occurs when individuals speak the sounds that they have heard another person pronounce or say. In other words, it is the saying by one individual of the spoken vocalizations made by another individual. Speech repetition requires the person repeating the utterance to have the ability to map the sounds that they hear from the other person's oral pronunciation to similar places and manners of articulation in their own vocal tract.

Phonemic contrast refers to a minimal phonetic difference, that is, small differences in speech sounds, that makes a difference in how the sound is perceived by listeners, and can therefore lead to different mental lexical entries for words. For example, whether a sound is voiced or unvoiced matters for how a sound is perceived in many languages, such that changing this phonetic feature can yield a different word ; see Phoneme. Other examples in English of a phonemic contrast would be the difference between leak and league; the minimal difference of voicing between [k] and [g] does lead to the two utterances being perceived as different words. On the other hand, an example that is not a phonemic contrast in English is the difference between and. In this case the minimal difference of vowel length is not a contrast in English and so those two forms would be perceived as different pronunciations of the same word seat.

Developmental verbal dyspraxia (DVD), also known as childhood apraxia of speech (CAS) and developmental apraxia of speech (DAS), is a condition in which an individual has problems saying sounds, syllables and words. This is not because of muscle weakness or paralysis. The brain has problems planning to move the body parts needed for speech. The individual knows what they want to say, but their brain has difficulty coordinating the muscle movements necessary to say those words.

Prosodic bootstrapping in linguistics refers to the hypothesis that learners of a primary language (L1) use prosodic features such as pitch, tempo, rhythm, amplitude, and other auditory aspects from the speech signal as a cue to identify other properties of grammar, such as syntactic structure. Acoustically signaled prosodic units in the stream of speech may provide critical perceptual cues by which infants initially discover syntactic phrases in their language. Although these features by themselves are not enough to help infants learn the entire syntax of their native language, they provide various cues about different grammatical properties of the language, such as identifying the ordering of heads and complements in the language using stress prominence, indicating the location of phrase boundaries, and word boundaries. It is argued that prosody of a language plays an initial role in the acquisition of the first language helping children to uncover the syntax of the language, mainly due to the fact that children are sensitive to prosodic cues at a very young age.

D. Kimbrough Oller, also known as Kim Oller, is an American scientist who has contributed to the fields of the evolution of language, child phonology, speech-language pathology, and to the fields of bilingualism and second-language acquisition. He is currently Professor and Plough Chair of Excellence at the University of Memphis. He is also an external faculty member of the Konrad Lorenz Institute for Evolution and Cognition Research and a permanent member of the Scientific Advisory Board of the LENA Research Foundation of Boulder, Colorado. Oller was elected as a Fellow of the American Speech–Language–Hearing Association (ASHA) in 2004 and was granted the Honors of ASHA in 2013.

References

  1. ↑ Bernthal, J.E., Bankson, N.W., & Flipsen, P. (2009) Articulation and Phonological Disorders: Speech Sound Disorders in Children. (6th edition). Boston, MA: Pearson.[ page needed ]
  2. ↑ Hepper, Peter G; Shahidullah, Bs (August 1994). "The development of fetal hearing". Fetal and Maternal Medicine Review. 6 (3): 167–179. doi:10.1017/S0965539500001108.
  3. ↑ Lasky, Robert E.; Williams, Amber L. (March 2005). "The Development of the Auditory System from Conception to Term". NeoReviews. 6 (3): e141–e152. doi:10.1542/neo.6-3-e141.
  4. 1 2 Kuhl, Patricia K. (2004). "Early language acquisition: Cracking the speech code". Nature Reviews Neuroscience. 5 (11): 831–43. doi:10.1038/nrn1533. PMID   15496861. S2CID   205500033.
  5. ↑ Rvachew, Susan (August 2007). "Phonological Processing and Reading in Children With Speech Sound Disorders". American Journal of Speech-Language Pathology. 16 (3): 260–270. doi:10.1044/1058-0360(2007/030). PMID   17666551.
  6. ↑ Hazan, Valerie; Barrett, Sarah (October 2000). "The development of phonemic categorization in children aged 6–12". Journal of Phonetics. 28 (4): 377–396. doi:10.1006/jpho.2000.0121.
  7. ↑ Nathani, Suneeti; Ertmer, David J.; Stark, Rachel E. (2009). "Assessing vocal development in infants and toddlers". Clinical Linguistics & Phonetics. 20 (5): 351–69. doi:10.1080/02699200500211451. PMC   3412408 . PMID   16728333.
  8. ↑ Oller, J. W.; Oller, S. D.; Badon, L. C. (2006). Milestones: Normal Speech and Language Development Across the Life Span. San Diego: Plural Publishing.[ page needed ]
  9. ↑ Sander, Eric K. (February 1972). "When are Speech Sounds Learned?". Journal of Speech and Hearing Disorders. 37 (1): 55–63. doi:10.1044/jshd.3701.55. PMID   5053945.
  10. ↑ Templin, Mildred C (1957). Certain language skills in children their development and interrelationships. Vol. 26. University of Minnesota Press. doi:10.5749/j.ctttv2st. ISBN   978-1-4529-3841-7. JSTOR   10.5749/j.ctttv2st. OCLC   580637663.[ page needed ]
  11. ↑ Wellman, Beth L; Mengert, Ida Gaarder; Bradbury, Dorothy Edith (1931). "Speech sounds of young children". University of Iowa Studies in Child Welfare. 5 (2): 1–82. OCLC   1942802.
  12. ↑ "Age of customary consonant production" (PDF). American Speech-Language-Hearing Association. Archived from the original (PDF) on 2022-03-24.
  13. ↑ Shriberg, Lawrence D. (1993). "Four New Speech and Prosody-Voice Measures for Genetics Research and Other Studies in Developmental Phonological Disorders". Journal of Speech, Language, and Hearing Research. 36 (1): 105–40. doi:10.1044/jshr.3601.105. PMID   8450654.

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