Mary Elbert

Statistical analysis of word-initial /k/ and /t/ produced by normal and phonologically disordered children

The acoustic characteristics of voiceless velar and alveolar stop consonants were investigated for normally articulating and phonologically disordered children using spectral moments. All the disordered children were perceived to produce /t/ for /k/, with /k/ being absent from their phonetic inventories. Approximately 82% of the normally articulating childrens consonants were classified correctly by discriminant function analysis, on the basis of the mean (first moment), skewness (third moment) and kurtosis (fourth moment) derived from the first 40 ms of the VOT interval. When the discriminant function developed for the normally articulating children was applied to the speech of the phonologically disordered group of children, no distinction was made between the velar and alveolar stops. Application of the model to the speech of individual children in the disordered group revealed that one child produced distinct markings to the velar-alveolar contrast. Variability measures of target /t/ and /k/ utteranc...

Spectral analysis of target-appropriate /t/ and /k/ produced by phonologically disordered and normally articulating children

Previous research (Forrest, Weismer, Hodge, Dinnsen and Elbert, 1990) has shown that some phonologically disordered children differentially mark seemingly homophonous phonemes; however, the resulting contrast may be spectrally distinct from that produced by normally articulating children of the same age. In the present investigation possible sources for these differences between normally articulating and phonologically disordered childrens productions of target-appropriate phonemes were pursued. Spectral characteristics of seemingly correct productions of /t/ and /k/ in word-initial position were analysed for four normally articulating and seven phonologically disordered children to assess the effect of recency of acquisition, depth of knowledge of the contrast and/or the effect of a phonological disorder on accuracy and variability of production. Results revealed that children who had acquired the velar-alveolar contrast more recently, and who had incomplete knowledge of that contrast, produced target-appropriate /t/ and /k/ differently from their normally articulating peers and other phonologically disordered children with greater knowledge of the contrast. Further, the phonologically disordered children with incomplete knowledge of the velar-alveolar contrast were less variable than the other phonologically disordered or normally articulating children in the spectral characteristics across repeated productions. Analysis of the spectral characteristics of word-initial /t/ and /k/ at a later point in time indicated similarities between all speaker groups in the spectral parameters that distinguished the velar from the alveolar stop. However, the stability of these parameters across repeated productions decreased for the phonologically disordered children with greater knowledge of the contrast. These effects are related to motor skill development and found to be consistent with previously demonstrated patterns of skill acquisition.

The Relationship Between Stimulability and Phonological Acquisition in Children With Normally Developing and Disordered Phonologies

The relationship between stimulability and phonological acquisition was investigated in eight children, four with phonological disorders who were aged 3;10 (years;months) to 5;7 and four with norma...

On the lawfulness of change in phonetic inventories

Changes in the phonetic inventories of 34 children (ages 3;4 to 6;8) with functional (nonorganic) speech disorders were analyzed in terms of distinctive feature oppositions. All subjects received conventional minimal pair contrast treatment to induce changes in their phonetic inventories. The changes were found to be governed by the same principles that govern cross-sectional variation before treatment. Sounds were added (or lost) consistent with implicational relationships among feature distinctions as set forth in Dinnsen, Chin, Elbert and Powell (1990).

Impact of substitution patterns on phonological learning by misarticulating children

Learning and generalization of treated sounds to different word positions is a desired outcome of intervention in the phonologically disordered childs system. Unfortunately, children do not always learn the sound that is treated; nor do they always demonstrate across-word generalization. One possible explanation for differences in treatment outcome may relate to the pretreatment substitution patterns used by different disordered children. This post-hoc analysis of treatment data examines the effects on sound learning and generalization of consistent versus inconsistent substitutes. With a consistent substitute across-word position (CS), the same phone was used in initial, medial and final position for a phoneme that was not in the childs inventory. An inconsistent substitute was evidenced by a different phone for a target sound in each position of a word (InAP), or even within word position (InWP) for an error sound. Fourteen children with severe phonological disorders were treated on an obstruent in in...

Facilitating [s] production in young children: an experimental evaluation of motoric and conceptual treatment approaches.

Eighteen phonologically disordered children were assigned to one of two experimental treatment programmes. Half of the children received a motoric treatment, which focused on establishing sound production in isolation, words, and phrases. The remaining children received a conceptual treatment, which sought to establish the phonemic nature of /s/ without providing motor practice. Treatment efficacy was evaluated by analysing [s] production during administration of a generalization probe. The motoric treatment was more effective overall; although some subjects, whose phonetic inventory included [s] prior to treatment, generalized correct production following the introduction of the conceptual treatment.

Consideration of Error TypesA Response to Fey

In this article the use of the term phonological to describe disordered speech patterns is discussed. In adopting the term, it seems important to give equal consideration to both the articulatory aspects and the more cognitive aspects of the problem. Viewing the phonological system as a whole highlights the different types of errors within the system. It is suggested that phonological disorders include both phonetic and phonemic error types and that the distinction between the two error types is useful in both assessment and treatment. Describing errors as either phonetic or phonemic types may lead to differential treatment procedures that are most appropriate for specific error types.

Patterns of sound change in children with phonological disorders

This paper presents longitudinal data that provide insight into the phonological learning of five children. These children were superficially similar in that all presented with errors affecting production of [s]; however, it will be argued that each child possessed a phonological system that was unique in certain ways. Production of [s]was established with each participant using a motoric training approach, and generalization was assessed over a 3-4-month period using a 50-item probe. Once treatment was initiated, changes in the production of [s]and in other properties of the phonological systems were observed. Some of these changes illustrated apparent learning strategies that were child-specific, whereas other changes were common to all of these children and may, in fact, be universal in nature.

The Indiana speech training aid (ISTRA)

The ISTRA system is being developed to improve the speech of deaf or misarticulating children. The system consists of a microcomputer equipped with a low‐cost, speaker‐dependent speech recognizer. One‐line feedback concerning the quality of entire utterance is derived from the degree of match between a stored template and the new utterance. Software for conducting speech training (under the guidance of a speech pathologist) has been developed over 3 years based on the collaboration of research scientists, clinicians, and programmers. Clients are able to run their speech drills independently using a variety of drills in game formats. Ongoing clinical evaluation of ISTRA training has employed single‐subject design experiments. In these studies, “blind” listener juries rated the speech of words collected before, during, and after training. Results show significant improvement of the quality of words trained in the ISTRA drill, as well as generalization to nontrained words. One ISTRA system has been used for regular speech training in an elementary school with positive results, both for improved speech as well as enthusiastic acceptance of the device. A description of the results of 3 years of research with ISTRA will be presented. [Research supported by NSF.]

[s] spectra in the speech of normally‐articulating preschool children and adults

[s] spectra from the speech of seven normally articulating pre‐school children, and seven normally articulating young adults have been obtained from utterances recorded under highly controlled conditions [see Weisruer and Elbert, J. Acoust. Soc. Am. 67, S39 (1980)]. Spectral analysis is accomplished in the frequency range 0–10 kHz by sampling the middle 50 ms of [s] waveforms with a fixed‐bandwidth, real‐time analyzer (Spectral Dynamics SD 335). Several different types of analysis reveal the following: 1) Peak energy locations are fairly stable within adult subjects, but relatively unstable within child subjects, and 2) spectral shape for child and adult subjects tend to be dissimilar. These results are taken to be additional confirmation that children control their speech mechanisms less efficiently than adults, and may suggest that children have [s] source characteristics (that is, articulatory constriction shapes) which differ from the corresponding adult characteristics in systematic ways. [Work suppo...