This chapter discusses the fundamental role of language in human communication and the unique linguistic needs of special populations, including those with autism, aging-related issues, Parkinson's disease, aphasia, and stuttering. It emphasizes the importance of tailored approaches to improve communication and quality of life for these groups, with a focus on assessment, intervention, and support. The chapter also categorizes special populations into groups with distinct language needs and challenges, such as speech disorders, cognitive impairments, and autism spectrum disorder.

1.1 Population With Speech Disorders

This chapter discusses recent research advancements in assisting individuals with aphasia, including the development of Brain-Computer Interfaces (BCIs), Repetitive Transcranial Magnetic Stimulation (rTMS), and Online Therapy Platforms. It also highlights progress in genetic studies, voice control feedback and machine learning, and processing in children with cochlear implants in relation to stuttering. These developments offer potential interventions and therapies to improve language abilities and communication for individuals with speech disorders.

1.2 Aging Population

This chapter discusses recent developments in research on aging population, focusing on interventions to support older adults’ cognitive and linguistic abilities. Key areas of progress include cognitive training programs, hearing aids and cochlear implants, and communication partner training. These advancements highlight the importance of cognitive training, hearing interventions, and communication strategies in supporting language and cognitive function in aging populations, offering promising pathways for enhancing quality of life and communication abilities in older adults.

1.3 Population With Parkinson’s Disease

This chapter discussed the impact of Parkinson’s disease on speech production, as well as the latest developments in research and therapeutic interventions for addressing speech and motor function impairments in patients with PD. Specifically, it highlighted the role of dopamine neurons and O-GlcNAcylation in Parkinson’s disease, the potential of virtual reality-based rehabilitation for motor function recovery, and the ongoing PD COMM trial evaluating the effectiveness of Speech and Language Therapy (SLT) interventions. These developments offer hope for improving the quality of life for individuals with Parkinson’s disease.

1.4 Population With Autism Spectrum Disorder (ASD)

The chapter discusses advancements in screening tools for ASD in racially diverse populations, the impact of social support on parental posttraumatic growth, and the development of innovative AAC technology for minimally verbal children with ASD. The studies highlight the importance of equitable access to accurate screening tools, the moderating effects of social support on parental experiences, and the potential of AI-driven AAC solutions to enhance communication for minimally verbal children with ASD. These findings contribute valuable insights into early ASD identification, parental experiences, and technology-driven solutions aimed at supporting children with ASD.

1.5 Summary

This chapter provides a summary of research into language for special populations, which aims to understand and address their unique communication needs. It discusses recent advancements in research on language for special populations, including individuals with autism, speech disorders, aging-related cognitive decline, and Parkinson’s disease, revealing targeted intervention strategies for each group. The chapter also explores the papers in the special issue, which focus on research into language for special populations, including speech disorders, aging, Parkinson’s disease, and Autism Spectrum Disorder (ASD).

2.1 Three Papers Related to Population With Speech Disorders

The chapter discusses three papers related to population with speech disorders. The first paper examines aphasia research from a linguistic perspective over the two decades, highlighting changes in research focus and emerging trends in the field. The second paper is a case study about idiom comprehension of Chinese patients with aphasia, aiming to determine if they can accurate understand the target meaning of idioms and to examine the impact of familiarity and context. The third paper investigates public attitudes towards people who stutter in China through a web-based written survey, finding predominantly negative attitudes across various aspects of life for people who stutter. Familiarity with people who stutter tended to reduce stereotypes, whereas media exposure might exacerbate them.

2.2 Two Papers Concerning Aging Population

This chapter discusses two papers concerning the aging population. The first paper examines power dynamics during cognitive assessment of older adults in a Chinese clinical setting, finding that both examiners and older adults use various speech acts to achieve different communicative goals, reflecting power dynamics between them. The other paper reviews cognitive research on language and aging, identifying major clusters and pivotal articles, as well as detecting emerging trends in the field. Major clusters identified include cognition, bilingualism, speech production, listening effort, reading comprehension, and Alzheimer's disease studies, with emerging trends including advancements in statistical methods and the relationship between language abilities and cognition.

2.3 One Paper Involving Population With Parkinson’s Disease

Dr. Qiang Li and his team investigated cepstral peak prominence (CPPs) in individuals with hypokinetic dysarthria related to Parkinson’s disease (PD) compared to healthy individuals. The study found significant differences in speech tasks, with CPPs in connected speech being more sensitive to dysphonia and gender differences in PD participants. The research suggests the need for a consistent clinical application protocol and multiple acoustic measures to ensure accurate clinical decisions.

2.4 One Paper Focusing on Population With Autism Spectrum Disorder (ASD)

This chapter discusses a scientific analysis conducted on the research landscape of language development in autistic children. The study identified key research clusters and trends, highlighting hotspots such as language disorder diagnosis and intervention, social communication, and language acquisition. The analysis also pointed out issues in current research and emphasized the need to expand interdisciplinary research on language development in autistic children. The research offers valuable references for autism researchers and practitioners, contributing to the existing literature. Additionally, the publication of this comprehensive issue aims to advance and promote research into the language used by special populations, fostering greater understanding and development within this critical area of study.