Articulation Test Research Articles

When No Speech Norms Exist: Observations From Sinhala.

A well-established set of language-specific norms for phonological development is imperative in the assessment of child speech sound difficulties. Currently, English norms are used clinically (in the absence of norms for local languages) to determine if a child displays age-appropriate, delayed or disordered speech patterns in Sinhala. This preliminary exploratory study aimed to document phonological processes observed in typically developing Sinhala-speaking children aged 3;0-6;11 (years;months). The Test of Articulation and Phonology-Sinhala, a picture-based assessment, was devised by the researchers and administered to 102 Sinhala-speaking children from three geographical locations (Colombo, Kandy, and Gampaha). The quantitative measures included percent consonants correct, percent vowels correct, and percent phonemes correct, while the qualitative analysis identified phonological processes. The quantitative results showed a marked influence of age on phoneme production accuracy with over 75% consonants correct by 3 years 6 months. The qualitative findings demonstrate common typical phonological processes and less common phonological processes in Sinhala compared to the speech pathology and cross-linguistic literature. Common phonological processes included fronting, stopping, and weak syllable deletion widely documented in linguistic and speech-language pathology literature. Many shared phonological processes were observed between Sinhala and Sri Lankan Tamil, the two main local languages, including fronting of retroflex sounds and lateralization. The phonological process of denasalization of prenasalized stops was observed in Sinhala, with no documentation of the phonological process found within the mainstream speech-language pathology literature. These findings reinforce the need to document and use language-specific typical phonological processes in Sinhala given the implications for early and accurate identification of speech difficulties and intervention. https://doi.org/10.23641/asha.27068173.

Demystifying Velopharyngeal Dysfunction for Plastic Surgery Trainees Part 2: Speech Fundamentals and Perceptual Speech Assessment.

Velopharyngeal dysfunction (VPD) is the inability to achieve proper closure of the velopharyngeal (VP) port, affecting speech and swallowing. The gold standard for diagnosis is auditory-perceptual speech evaluation by a specialized speech-language pathologist. This 3-part series provides a comprehensive discussion on (1) the anatomy and physiology of the velopharyngeal mechanism, (2) fundamental speech terminology and principles of perceptual speech assessment for VPD, and (3) techniques for objective evaluation of the VP port and surgical decision-making process. In part 2, the authros begin with the concepts and terminology required to understand the perceptual speech assessment of VPD, including resonance, articulation, and the differentiation between consonants and vowels. We review the types of speech samples used for evaluation such as single-word articulation tests, syllable repetition, sentence repetition, and spontaneous connected speech. Finally, we discuss the auditory-perceptual speech assessment for VPD, including the assessment of resonance, nasal air emission, articulation, and voice quality. The use of rating scales like the Pittsburgh Weighted Speech Scale (PWSS) and the Cleft Audit Protocol for Speech-Augmented-Americleft Modification (CAPS-A-AM) is highlighted. In addition, the significance of intraoral examinations, visual-tactile-auditory evaluations, and the assessment of voice quality are covered. Most textbook chapters discussing this topic assume a foundational knowledge of speech-language pathology, which a surgical trainee may lack. This study aimed to bridge the gap between surgical training and speech pathology, providing a comprehensive resource to enhance the understanding and management of VPD.

MED13L-related disorder characterized by severe motor speech impairment.

MED13L-related disorder is associated with intellectual disability, motor delay, and speech deficits. Previous studies have focused on broad clinical descriptions of individuals, but limited information regarding specific speech diagnoses and results of direct testing has been published to date. We conducted deep phenotyping to characterize the speech, language, motor, cognitive, and adaptive phenotypes of individuals with MED13L-related disorder. In this cross-sectional study, we administered standardized articulation, language, motor, and cognitive testing to 17 children and adolescents (mean age 9y 9m; SD 4y 5m; range 4y 2m to 19y 7m). In-person testing was supplemented with broad developmental, medical, and behavioral information collected virtually from a cohort of 67 individuals. All individuals who completed in-person articulation testing met diagnostic criteria for speech apraxia, dysarthria, or both. Language impairment was present in all of the in-person cohort and almost all (97%) of the virtual cohort. Those who were able to complete motor testing demonstrated significant deficits in visual motor integration (mean 57.08, SD 9.26). Full scale IQs fell in the borderline to intellectual disability range, consistent with reported cognitive impairment in 97% of the virtual cohort. Notable medical features included hypotonia (83%), vision problems (72%), recurrent otitis media (58%), gastrointestinal problems (57%), and seizures (31%). MED13L-related disorder is characterized by a high rate of motor speech disorders that occur in the context of globally impaired motor, language, and cognitive skills. Children would benefit from intensive, individualized speech therapy and the early adoption of augmentative communication strategies.

‘‘Language profile among Arabic-speaking children with attention deficit hyperactive disorder”

BackgroundChildren with ADHD were found to have language impairment in many studies. The way they use language in their everyday life may be affected, namely, the pragmatic aspect of language. Measuring the affected parameters in all aspects of language will help to reach better rehabilitation. Thus, this study set out to observe relationships between hyperactivity/impulsivity and inattention with all language domains in 30 Egyptian Arabic-speaking children with ADHD between 4 and ≤7 years old with the aim of better intervention. Children were evaluated to establish the diagnosis of ADHD and its type following the diagnostic criteria of the DSM-V criteria and the Conners’ Parent Rating Scale-Revised. Language abilities were assessed by the Pre-school Language Scale 4th edition (Arabic version), the Arabic articulation test, and the Egyptian Arabic Pragmatic Language Test. This assessment covered receptive and expressive language abilities and phonological and pragmatic skills. ResultsCompared to norms, it was found that the ADHD children who participated in this study had non-significant language delays in the parameters of the modified PLS-4 test. 70 % of the ADHD children had total pragmatic test scores below their 5th percentile, while 30 % of the children had total pragmatic test scores above their 5th percentile. 50 % of ADHD children failed to master certain sounds corresponding to their phonological age. A statistically significant negative correlation was observed between each of the inattention and hyperactivity/impulsivity scores and the receptive, expressive, total language ages, and pragmatic language scores. ConclusionChildren with ADHD in this study did not show major difficulties in areas beyond what would be expected in normally developing children. Most children with ADHD in the present study had problems with pragmatic language aspects that are correlated positively to ADHD symptoms. 50 % of ADHD children failed to master certain sounds corresponding to their chronological age.

Consonant Cluster Acquisition in Toddlers: An Explorative Study

The acquisition of consonant clusters is considered as one of the final stages of speech development in typically developing children. Nonetheless, the phonological development in children is now more advanced compared to the previously established norms. The current study aimed to determine how consonantal clusters, in particular non-geminate clusters, emerged throughout the early phases of phonological acquisition and to understand the positional variations in the cluster acquisition. The study involved 40 Malayalam speaking children aged between two to three years, divided into four groups with an age interval of 3 months. These children were administered 30 non-geminate consonant clusters from the Malayalam Articulation Test – Revised. Positional effect of the cluster acquisition was examined. In addition, the type of articulatory errors on consonant production were also determined. Findings from the present study revealed that children achieve the mastery of many consonant clusters by two to three years of age. Positional effect of cluster acquisition revealed medial clusters were acquired earlier than initial clusters. Cluster reduction was the dominant cluster error type, decreasing with age. Thus, compared with the previous established norms, the current findings demonstrate a much earlier acquisition of nongeminate clusters in Malayalam. The revised norms for cluster acquisition proposed from the findings of this study could benefit Speech-Language Pathologists to conduct age-appropriate assessment and treatment of speech sound disorders.

Acquisition of Gutturals by Ammani-Jordanian Arabic-Speaking Preschoolers.

This study aims at investigating the phonological development of the six guttural consonants of Jordanian Arabic, /χ/, /ʁ/, /ħ/, /ʕ/, /ʔ/, and /h/. An articulation test is designed to involve two tasks: picture naming and repetition. The test includes 54 words for picture naming and 18 words for repetition, representing all possible positions of the targeted guttural sounds. Samples are collected from 40 typically developing Ammani-Jordanian Arabic-speaking monolingual children, living in Amman, Jordan. Respondents are equally divided into eight age-related trajectories: 2-2;6, 2;6-3, 3-3;6, 3;6-4, 4-4;6, 4;6-5, 5-5;6, and 5;6-6 (years;months). No child with a history of hearing, speech, or vision disorders is included. The data are analyzed using production accuracy, where the three developmental trajectories of production (customary, acquisition, and mastery) are determined for each guttural, and error analysis, addressed based on perceptual judgments, providing details of every mispronounced or deleted guttural. The results show that /χ/, /ħ/, /ʕ/, and /ʔ/ are acquired before the age of 6 years, while /ʁ/ and /h/ are still not acquired by this age. Respondents use relatively variant alternatives for the mispronounced cognates, including guttural, nonguttural sounds, and vowel substitution. The /ʁ/ is the guttural with the highest number of alternatives, while /ʔ/ gets the least. The analysis also reveals patterns of guttural deletion, with variations across different guttural sounds and positions. Despite errors/deviations made, respondents score accuracy percentages that gradually increase in correlation with age. The guttural /ʁ/ starts with the lowest accuracy percentages, while /ʔ/ and /ħ/ start with the highest. These findings illuminate on the developmental trajectory of guttural acquisition and enrich our understanding of children's evolving perception and production abilities. They offer valuable insights into the patterns of guttural sound production in Jordanian Arabic-speaking children, laying the groundwork for further research and the development of targeted assessment and intervention strategies to support phonological development in this population.

Comparative analysis of natural and synthesized Polish speech

In the evolving field of speech synthesis, not only intelligibility, but also naturalness remains an important factor. This paper presents a comparative analysis of natural versus synthesized Polish speech. Speech synthesizers: Ivona, Mekatron, Notevibes, and ttsmp3 were explored. Four methods for assessing synthesized speech quality and comparing it to natural speech were presented: the AB test, MOS, logatom articulation test, and MUSHRA. Sentence databases and a database of logatoms were generated for each synthesizer and recorded for natural speech. Results indicated natural speech was consistently better than synthesized speech. Among the synthesizers, Notevibes performed best in all comparisons, while Mekatron ranked lowest.

Speech production in Vietnamese-English bilingual speakers living in a 3-generation home

ABSTRACT Without data on speech accuracy of Vietnamese-English speakers, speech-language pathologists (SLPs) are unable to assess accurately this population for speech sound disorders. This study explored the heretofore uninvestigated speech accuracy and use of Vietnamese-English bilingual individuals residing in the USA. Participants included six individuals from a 3-generation household (two US-born children and four Vietnam-born adults). Each participant completed a language history questionnaire and single-word articulation tests in Vietnamese and English. Percentage Consonants Correct – Revised and Percentage Consonant Clusters Correct were compared across participants and generations. Phoneme errors were analysed to identify adult influence on child productions. Heritage language use and speech accuracy generally showed an inverse relationship with length of stay, but the children’s productions were nearly without error in both languages. Only the mother exerted apparent influence on the children’s speech development, though only in Vietnamese. The children’s English productions were unaffected by any adult’s productions. Clinicians working with children from this background should consider not only familial influence on speech sound accuracy but should anticipate high levels of speech accuracy in both English and Vietnamese. When working with adults, SLPs should be aware that deviant speech productions might be due to typical Vietnamese-English speech development.

Productions of Goldman-Fristoe Test of Articulation–Third Edition Stimulus Words Among Teenage Speakers of Anguillian Eastern Caribbean English

Purpose: This study documents consonant and vowel variation in typically developing teenage speakers of Anguillian English, demonstrates how consonant variation impacts performance on the Goldman-Fristoe Test of Articulation–Third Edition (GFTA-3), and provides culturally responsive clinical recommendations for GFTA-3 scoring involving native speakers of Anguillian English. Method: Twenty Anguillian teenagers (14;3–17;9 [years;months]) completed the GFTA-3 Sounds in Words subtest. The audio-recorded productions were phonetically transcribed and analyzed to determine consonant and vowel variations that differed from Mainstream U.S. English. To demonstrate the importance of culturally responsive assessment, deficit scores were compared with language-appropriate scores. Results: Anguillian consonant variation heavily impacted GFTA-3 stimuli that were meant to elicit /ɚ/, postvocalic /ɹ/, interdental fricatives, and present participle /ŋ/. Vowel variations included production of /ʌɪ/ in knife, /ɑɪ/ in boy, and /oʊ/ in house. Some speakers demonstrated more consistent use of Anguillian speech variation than others. When language-appropriate scoring was not used, 19 of the 20 participants scored below the first percentile in the Sounds in Words subtest. Conclusions: Culturally and linguistically responsive practices and tools are needed throughout the Eastern Caribbean region. This study's description of Anguillian English speech variation in GFTA-3 stimuli is a resource that will improve culturally responsive speech sound assessment in Anguillian children. We encourage clinicians and researchers to replicate this study with speakers of other Eastern Caribbean English languages.

Characterization of speech and language phenotype in the 8p23.1 syndrome.

The 8p23.1 duplication syndrome is a rare genetic condition with an estimated prevalence rate of 1 out of 58,000. Although the syndrome was associated with speech and language delays, a comprehensive assessment of speech and language functions has not been undertaken in this population. To address this issue, the present study reports rigorous speech and language, in addition to oral-facial and developmental, assessment of a 50-month-old Turkish-speaking boy who was diagnosed with the 8p23.1 duplication syndrome. Standardized tests of development, articulation and phonology, receptive and expressive language and a language sample analysis were administered to characterize speech and language skills in the patient. The language sample was obtained in an ecologically valid, free play and conversation context. The language sample was then analyzed and compared to a database of age-matched typically-developing children (n = 33) in terms of intelligibility, morphosyntax, semantics/vocabulary, discourse, verbal facility and percentage of errors at word and utterance levels. The results revealed mild to severe problems in articulation and phonology, receptive and expressive language skills, and morphosyntax (mean length of utterance in morphemes). Future research with larger sample sizes and employing detailed speech and language assessment is needed to delineate the speech and language profile in individuals with the 8p23.1 duplication syndrome, which will guide targeted speech and language interventions.

Development of Phonological Error Patterns in Arabic-Speaking Children in Jordan

This study aims to identify the phonological error patterns of normally developing children who speak colloquial Jordanian Arabic dialect and to provide normative data for the age of suppression for each phonological error pattern. One hundred fifty-four normally developing children (68 females and 86 males) ranging from 3 to 6.5 years were recruited from nurseries and kindergartens in the cities of Amman and Salt to participate in the present study. Data collection was performed in a quiet room (Ambient noise <30 dB A) using Amayreh’s articulation test. Two speech-language pathologists (SLPs) scored the responses of each participant independently. The phonological error pattern is considered present if it is produced in five different words by the child in single-word productions and present in 10% of the children in any age group. Some phonological error patterns were not evident in normally developing Jordanian Arabic–speaking children (e.g., cluster reduction, affrication, and deaffrication). Most phonological error patterns disappeared at the age of 5.5 to 6 years. Fronting was the only pattern that existed after the age of 6. Linguistic and dialectical features can vastly affect these patterns and their suppression. Therefore, obtaining normative data for different Arabic dialects is needed and has important clinical implications for diagnosing phonological disorders, treatment planning, and assigning intervention targets.

Development of Articulation Test in Garhwali Language: A Preliminary Study

Development of Articulation Test in Garhwali Language: A Preliminary Study

Speech Task Force and Quality of Life after Surgery in Children with Cleft Lip and Palate: Limitation of Professionals.

Background Shortage of speech and language therapists results in lack of speech services. The aims of this study were to find the effectiveness of a combination speech therapy model at Level IV: General speech and language pathologist (GSLP) and Level V: Specific speech and language pathologist (SSLP) in reduction of the number of articulation errors and promotion the quality of life (QoL) for children with cleft palate with or without cleft lip (CP ± L). Methods Fifteen children with CP ± L, aged 4 years 1 month to 10 years 9 months (median = 76 months; minimum:maximum = 49:129 months) were enrolled in this study. Pre- and post-assessment included oral peripheral examination; articulation tests via Articulation Screening Test, Thai Universal Parameters of Speech Outcomes for People with Cleft Palate, Hearing Evaluation, The World Health Organization Quality of Life Brief_Thai (WHOQOL-BRIEF-THAI) version questionnaire for QoL were performed. Speech therapy included a 3-day intensive speech camp by SSLP, five 30-minute speech therapy sessions by a GSLP, and five 1-day follow-up speech camps by SSLP that provided four 45-minute speech therapy sessions for each child. Results Post-articulation revealed statistically significant reduction of the numbers of articulation errors at word, sentence, and screening levels (median difference [MD] = 3, 95% confidence interval [CI] = 2-5; MD = 6, 95% CI = 4.5-8; MD = 2.25, 95% CI = 1.5-3, respectively) and improvement of QoL. Conclusion A speech task force consisting of a combination of Level IV: GSLP and Level V: SSLP could significantly reduce the number of articulation errors and promote QoL.

Speech therapy screening project in the islands of Lampedusa, Linosa and Ustica

In the general population of 5-year-old children, those with Specific Language Disorders represent about 7%. The difficulties, which are more evident in the first years of life, often continue into school age, for this reason, it is of crucial importance to promptly intercept these health needs to guarantee the management and resolution of linguistic difficulties which, if not treated, will transition to the area of school learning. This work aims to identify children at risk concerning language development. The screening program involved all classes of nursery school and the first and second year of primary school, evaluating possible linguistic problems in the 6-8 age group. The speech therapy screening involved the administration of the Articulation Test. From the analysis of the data, it emerged that 12% of the participants, i.e. 21 children (11 children resident in the municipality of Lampedusa and Linosa, 10 children resident in the municipality of Ustica) were identified as at risk for language delay. For children identified at risk, an in-depth clinical-diagnostic investigation was requested. From this experience of prevention and awareness at an early age for language disorders, the importance of identifying risky situations early on is evident to support the correct evolution of verbal production and avoid that a late intervention could make the most serious situation. Nursery school represents a crucial place and moment for recognizing a possible difficulty. Unfortunately, attention to children's language is not yet optimal and is often directed only to those cases that show obvious signs of delay. This is why early identification of difficulties and timely management by the speech therapist is so important.

Comparing pronunciation challenges in South Korean preschoolers with unilateral single-sided deafness due to cochlear nerve deficiency to a norm-referenced standard.

This study aimed to compare the development of pronunciation in South Korean preschoolers with unilateral cochlear nerve deficiency (CND) to that of age-matched preschoolers with normal hearing, a topic that has not been explored previously. In a retrospective analysis, 25 preschoolers with unilateral CND who had undergone a speech evaluation battery, including a pronunciation and vocabulary test, were enrolled. Utilizing the Urimal Test of Articulation and Phonation and customized language ability tests, pronunciation and vocabulary were assessed. The subjects' speech evaluation scores were converted into age-adjusted z-scores using normal controls' data. While vocabulary performance was within normal limits, their average pronunciation z-score was -2.90, significantly lower than both the zero reference point and their vocabulary z-scores. None of the subjects scored above average in pronunciation. Thirteen patients were recommended for articulation therapy, seven were considered as potential candidates for this therapy, and the remaining five were within normal limits. There was no observed correlation between the development of pronunciation and vocabulary. Notably, some subjects' pronunciation scores did not improve, even after serial follow-up during their preschool years. Despite typical vocabulary development, preschoolers with unilateral CND exhibit significant delays in pronunciation. These findings emphasize the necessity for vigilant monitoring of their language development.

Construction of polyurethane composites incorporating borate ester and B-N coordinative bonds: Achieving ultra-high fracture energy, self-healing property, and facile recyclability for wearable sensors

In recent years, there has been a notable surge in research focusing on the utilization of polyurethane (PU) in flexible wearable electronic devices. Consequently, it is essential to incorporate attributes such as high stretch, self-healing, and easy recyclability into PU. However, the suboptimal compatibility of PU with conductive fillers poses a significant challenge. This paper details the synthesis of a highly stretchable, self-healing, and easily recyclable PU elastomer, utilizing borate ester bonds and B-N mating bonds as the composite matrix. Highly conductive flexible composites were fabricated, employing multi-walled carbon nanotubes (CNTs) and graphene nanosheets (GNSs) as fillers. These composites exhibit excellent fracture energy, self-healing ability, and tensile strength due to the synergistic interaction of borate bonds, B-N ligand bonds, and hydrogen bonds. The fracture energy achieves an impressive 109.4 KJ·m−2, with a noteworthy 79% self-healing efficiency. Furthermore, the materials demonstrate mechanical properties, including a tensile strength of 66.5 MPa and an exceptionally high elongation at break of 2792%. The flexible conductive composites present high electrical conductivity (6.86 S/m) and sensitivity (GF：9.45). In its capacity as a flexible conductive composite, it can accurately detect human behaviors, such as finger flexion, facial expressions, throat articulation tests, and more. Therefore, it has potential applications in various fields, including wearables, robotic skin, and health monitoring.

In an EFL Environment: Characteristics of Speech Sound Disorders in Children’s English Articulation

Objectives: In an EFL (English as a Foreign Language) environment like Korea, individuals learn English through education, and learning a foreign language is naturally influenced by the language system of the mother tongue. This study aimed to investigate the English speech characteristics and patterns of native language transfer in children with speech sound disorders (SSD).Methods: 20 Korean children aged 4-6 years participated in this study. The study divided participants into SSD and normal speech acquisition (NSA) groups, each comprising 10 children. Participants completed English word repetition task using the Diagnostic Evaluation of Articulation and Phonology (DEAP). Additionally, the SSD group was assessed using the Urimal Test of Articulation & Phonology (U-TAP) to compare differences in speech production based on language types. In both groups, the overall consonant accuracy, error types an error patterns in English were analyzed. English error types were categorized as substitution, vowel addition, consonant addition, vowel deletion, consonant deletion, inter-language distortion and intra-language distortion. Error patterns were further divided into developmental and non-developmental error patterns.Results: The SSD group demonstrated lower consonant accuracy compared to the NSA group in English articulation. Significant differences were observed between the two groups in vowel deletion rates and minor variations in consonant addition patterns. Error pattern analysis revealed that both groups exhibited a high proportion of stopping and final consonant deletion.Conclusion: This study directly confirmed the transfer of native language deficits in children with SSD to their English articulation and indirectly suggested that underlying deficits might impact English speech production.

Comparison of Traditional Articulation Therapy and Picture Articulation Test in Children with Articulation Disorders

Background: Articulation disorders in children can impede communication and social interaction. Traditional Articulation Therapy (TAT) and the Picture Articulation Test (PAT) are two contrasting approaches employed to address these disorders. While TAT is a conventional method focusing on sensory-perceptual training and sound stabilization, PAT uses visual aids to assess and encourage correct speech sound production. Objective: The study aimed to evaluate and compare the efficacy of TAT and PAT in treating substitution errors in children with articulation disorders. Methods: Employing a randomized sampling technique, the study included 10 children with functional articulation disorders, aged 8 to 18 years, from both genders. Exclusion criteria included organic articulation disorders. Participants were divided into two groups at REX Medical Center, Lahore, and treated over a six-month period, with two sessions per week lasting 30-40 minutes. Pre- and post-intervention assessments were conducted using the Articulation Assessment Test and the Articulation Severity Rating Scale. Data analysis was performed using SPSS 24, with paired and independent sample t-tests. Results: TAT showed a significant reduction in substitution error scores from pre- to post-intervention across all error types (initial, middle, and final), with significant p-values indicating improvement (p ≤ 0.05). PAT did not demonstrate a significant reduction in error scores, with p-values exceeding the threshold of significance. Conclusion: TAT was found to be more effective than PAT in decreasing substitution errors in children with articulation disorders. The findings advocate for the application of TAT in clinical settings, while recognizing the potential for integrating traditional methods with newer technologies to optimize treatment outcomes.

Frequency-discrimination and speech-perception characteristics of bone-conducted sound presented to the facial parts

Bone-conducted (BC) sound is typically presented to the mastoid process of the temporal bone or the condyle process of the mandible. However, a method of presenting BC sound to facial parts such as the nose and cheek have also been investigated recently. Since the face is one of the most complex structures in the human body, slight differences in the presentation parts of the vibrator will also change the perception and propagation mechanism. However, the characteristics of BC sound presented to the face have not yet been studied in detail. We have previously discussed the differences in perception (hearing thresholds) and propagation characteristics among facial parts. Here, to test the frequency-discrimination ability, we measured difference limens for frequency. We also conducted monosyllable articulation tests in Japanese to assess the speech-perception characteristics when BC sounds are presented to various facial (nasal, infraorbital region, zygomatic, jaw angle, and chin) and conventional (mastoid and condyle process) parts. The results obtained showed that the frequency resolution and intelligibility of the facial parts were about the same as those of the conventional parts. It is indicated that practical frequency information and speech perception are possible with BC devices attached to certain facial parts.

Effect of occlusion effects by bone-conduction sound on speech perception assessed by monosyllable articulation test and confusion in phoneme perception

Bone conduction (BC) has been applied to hearing aids for conductive hearing loss, earphones, and other audio devices including ones presenting sound to the face. One of the important characteristics of BC is the "occlusion effect (OE)", a phenomenon that low-frequency sound are perceived as being enhanced when the ear canal is occluded. Our previous study examining OE in facial parts reported that the OE in some facial parts was larger than OE in parts conventionally used. In this study, we conducted monosyllable articulation tests using bone-conducted speech with subjects' ear canal open and occluded, and investigated confusion in phoneme perception to evaluate the effect of OE on perception in the mastoid process, condylar process, nasal bone, and infraorbital region. The results showed that OE increased articulation. However, its effect varied depending on stimulus location and acoustic characteristics of the phonemes, and even confusions among unvoiced consonants even increased by OE. These findings are useful for optimizing BC devices using OE.