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When the augmentative and alternative communication (ACC) model (Lloyd et al., 1990) was proposed, these components of symbols were not considered, nor were they contemplated when superordinate (Lloyd and Fuller, 1986) and subordinate levels (Fuller et al., 1992) of AAC symbol taxonomy were developed. The purpose of this paper is to revisit the ACC model and propose a new symbol classification system called multidimensional quaternary symbol continuum (MQSC)

The field of AAC is evolving at a rapid rate in terms of its clinical, social, research and theoretical underpinnings. Advances in assessment and intervention methods, technology and social issues are all responsible to some degree for the significant changes that have occurred in the field of AAC over the last 30 years. For example, the number of aided symbol collections has increased almost exponentially over the past couple of decades. The proliferation of such a large variety of symbol collections represents a wide range of design attributes, physical attributes and linguistic characteristics for aided symbols and design attributes and linguistic characteristics for unaided symbols.

Therefore, it may be time to revisit the AAC model and more specifically, one of its transmission processes referred to as the means to represent.

The focus of this theoretical paper then, is on the current classification of symbols, issues with respect to the current classification of symbols in terms of ambiguity of terminology and the evolution of symbols, and a proposal for a new means of classifying the means to represent.

The peer review history for this article is available at: https://publons.com/publon10.1108/JET-04-2021-0024

Graphic symbols have been used widely in the field of augmentative and alternative communication (AAC). The advancement of technology in recent years has stimulated their development even further, thereby providing speech-language pathologists (SLPs) a wide range of options to choose for the individuals they support. However, existing literature on graphic symbols is scant and clinicians must base their decisions almost solely on clinical judgment. This paper aims to investigate the factors SLPs consider when choosing corpuses of graphic symbols for their clients.

An online survey was used that allowed multiple-choice responses. Data were analyzed and presented primarily as percentages.

Most respondents used graphic symbols with people having developmental disorders, and the corpuses of symbols they drew upon were based predominantly on availability, characteristics of the individual’s impairment or disability and intelligibility to the user and his or her communication partners. Existing policies related to graphic symbols also influence clinicians’ choices. SLPs search for support mainly from professional associations and training providers. In terms of use with technology, ready-made symbol packages for clinicians to use were found to be attractive.

Professional associations and institutions that focus on AAC need to provide adequate support to clinicians with a foundation based on evidence-based practice.

To the best of the authors’ knowledge, this is the first research that focuses on current practices concerning the factors SLPs take into consideration when choosing the optimum graphic symbol corpus(es) for their clients.

Graphic symbols, such as the Picture Communication Symbols, Makaton and Widgit, have been traditionally used in the field of augmentative and alternative communication (AAC) in order to support people with little or no functional speech. The paper aims to discuss these issues.

However, given the fact that the terminology remains contested in the existing literature as well as the multidisciplinary nature surrounding graphic symbols, in more recent years and the number of terms used in different fields, it is vital that the terminology of graphic symbols is revisited again.

In the last section of the paper, a definition of graphic symbols is proposed.

The value of this paper lies in the fact that while field of graphic symbols have been used in the AAC for more than 30 years, there is still no consensus regarding the meaning of the terminology used.

The ongoing development of new graphic symbol sets in conjunction with a lack of literature supporting professionals in choosing the optimum set(s) for their users was the driving force behind this research project. The purpose of this paper is to explore the factors that professionals take into consideration when they choose one graphic symbol set instead of another.

Based on the phenomenology of pedagogy, semi-structured interviews were used with three speech and language therapists (SLTs), three special education teachers, one teacher for pupils with hearing loss, one foundation year teacher and one SENCo/deputy head teacher. Thematic analysis was used to process the data.

The results have shown that when professionals choose a graphic symbol set for their user(s), they focus on the iconicity, the software availability and its features. They are also influenced by any existing graphic symbol policies in the area they work. Training and follow-up support also influence professionals’ experiences when choosing graphic symbol sets for their users.

Given the limited literature pertaining to the topic of this paper, it is proposed that further research is conducted in order to build the theoretical and practical frameworks upon which professionals (such as SLTs and teachers), symbols developers and academics can base their future work.

This research aims to contribute to the scant literature regarding the factors that SLTs take into consideration when choosing a graphic symbol set for their user(s).

Although theories in the past claimed that in order to be literate someone has to acquire specific prerequisite skills, more recent theories suggest that for some aspects of language, symbols can help people to access literacy. In this paper, we speculate that symbols can help children in schools to cope with their difficulties with print. Widgit Literacy Symbols have been developed over the last 20 years as a means of enhancing access to written communication and curriculum. Through the Symbol Inclusion Project (SIP), Widgit Software has been working closely with teachers in Warwickshire, creating resources for students in schools. Anecdotal evidence from the SIP project suggests that symbols can help children to anticipate their difficulties with literacy as well as to increase their motivation and self‐esteem and improve their behaviour.

Given the rise of individuals who have complex communication needs (CCN), it is important to identify appropriate assistive technology systems that can support the individual's communication needs. Augmentative and alternative communication (AAC) systems can serve as a means to assist individuals to communicate independently. The goal of AAC is to enhance or replace the individual's current and limited verbal or written communication skills. This chapter focuses on feature matching, aided communication and the selection process for aided communication systems including low to high technology systems. It also emphasises other key considerations pertaining to person-centred planning such as conducting preference assessments and trial periods to minimise system abandonment.

Working memory (WM) is a key component of effective and efficient communication in typical communicators, with, potentially, even greater significance for those who benefit from augmentative communication. This study aims to explore the emergence of WM strategies in children with complex communication needs who may be reliant on aided communication strategies.

A quasi‐experimental repeated measures, multi‐factorial research design, comparing 30 children with complex communication needs (CCN) aged three to six years and 30 age‐matched typically developing peers. Picture stimuli representing verbs and adjectives in three categories: control words, long words and phonologically similar words are presented visually or silently in sequences of increasing length to establish each participant's memory span.

Articulatory rehearsal does not appear to be used as a memory strategy with verb material. With adjective material, there is limited evidence of emerging articulatory rehearsal at age six. Input modality does not influence rehearsal of either verbs or adjectives.

The study is small scale and exploratory, but there are suggestions that both groups of participants handle verb and adjective material differently to noun material.

Emerging WM skill in children with CCN needs to be considered in relation to the use of speech generating technology.

This paper contributes to understanding of the development and potential influence of WM in efficient aided communication.

This paper, a theoretical article, aims to revisit the augmentative and alternative communication (AAC) communication model and its transmission processes and interface as proposed by Lloyd, Quist and Windsor in 1990. More specifically, the focus of this paper is on the classifications of the SELECT (i.e. the means to select symbols) and TRANS (i.e. the means to transmit messages) components of the AAC transmission processes and interface.

The field of AAC is evolving at a rapid rate. As the field continues to evolve in terms of its clinical, social, research and theoretical underpinnings, it is incumbent upon academics and practitioners in AAC to be cognizant of terminological and theoretical changes that may be needed to keep pace with the evolution of the field.

The authors welcome feedback from academics and clinicians with the hope that a more thorough discussion will lead stakeholders to more accurate and descriptive terminology related to the means to select and transmit components of the AAC model transmission processes.

The goal of this article was to suggest that the aided versus unaided classification continue to be used to classify the means to select but a new taxonomy be adopted for the means to transmit, thereby eliminating the use of the terms high and low technology. Terminology developed to describe TRANS should be unambiguous, include both expressive and receptive communication and be clinically relevant. In the opinion of the authors, the proposed taxonomy meets all three of these criteria.

Researchers, subject specialists, and information professionals have long been aware of scientific and technical (sci‐tech) dictionaries available from the U.S. government. Yet these reference sources often remain invisible to the general public, especially in libraries that exclude government documents from the main catalog or that maintain separate documents collections. However, as more libraries automate their holdings and load cataloging records for government publications into their online public access catalogs (OPACs), government documents should become more visible. Until then, it may surprise some to learn that many U.S. government agencies have allocated vast resources into compiling, publishing, and updating technical dictionaries in print, microfiche, and electronic format.

The purpose of this paper is to demonstrate a proficiency for accomplishing optimal CFO and keep down the error among the received and transmitted signal. Orthogonal frequency-division multiplexing (OFDM) is considered as an attractive modulation scheme that could be adopted in wireless communication systems owing to its reliability in opposition to multipath interruptions under different subchannels. Carrier frequency offset (CFO) establishes inter-carrier interference that devastates the orthogonality between the subcarriers and fluctuates the preferred signal and minimizes the effectual signal-to-noise ratio (SNR). This results in corrupted system performance. For sustaining the subcarriers’ orthogonality, timing errors and CFOs have to be approximated and sufficiently compensated for. Single carrier modulation (SCM) is a major feature for efficient OFDM system.

This paper introduces a novel superposition coded modulation-orthogonal frequency-division multiplexing (SCM-OFDM) system with optimal CFO estimation using advanced optimization algorithm. The effectiveness of SCM-OFDM is validated by correlating the transmitted and received signal. Hence, the primary objective of the current research work is to reduce the error among the transmitted and received signal. The received signal involves CFO, which has to be tuned properly to get the signal as closest as possible with transmitted signal. The optimization or tuning of CFO is done by improved grey wolf optimization (GWO) called GWO with self-adaptiveness (GWO-SA). Further, it carries the performance comparison of proposed model with state-of-the-art models with the analysis on bit error rate (BER) and mean square error (MSE), thus validating the system’s performance.

From the analysis, BER of the proposed and conventional schemes for CFO at 0.25 was determined, where the adopted scheme at 10th SNR was 99.6 per cent better than maximum likelihood, 99.6 per cent better than least mean square (LMS), 99.3 per cent better than particle swarm optimization (PSO), 75 per cent better than genetic algorithm (GA) and 25 per cent better than GWO algorithms. Moreover, MSE at 1st SNR, the proposed GWO-SA scheme, is 4.62 per cent better than LMS, 60.1 per cent better than PSO, 37.82 better than GA and 67.85 per cent better than GWO algorithms. Hence, it is confirmed that the performance of SCM-OFDM system with GWO-SA-based CFO estimation outperformed the state-of-the-art techniques.

This paper presents a technique for attaining optimal CFO and to minimize the error among the received and transmitted signal. This is the first work that uses GWO-SA for attaining optimal CFO.