Speech-language therapists (SLTs) play a vital role in supporting both receptive and expressive language development across oral and written modalities. Their work spans speech sound correction, oral language skills and phonological awareness, as well as early literacy skills, such as print knowledge, spelling, reading comprehension and fluency – underscoring their essential contribution within mainstream education settings (Stephenson et al., 2024). Children who cannot rely on speech alone to meet their communication needs are routinely placed in schools for learners with special educational needs (LSEN schools) (Department of Education [DoE], 2001). In these settings, the role of SLTs expands to include the assessment, diagnosis and treatment of learners with a range of speech and language impairments resulting from varying conditions (Sharma, 2021). Many learners in LSEN schools would benefit from the implementation of augmentative and alternative communication (AAC) to support either receptive or expressive language. According to Beukelman and Light (2020), AAC employs a range of strategies and tools, including unaided approaches such as manual signs, gestures and finger spelling, as well as aided approaches, which involve tangible objects, line drawings and graphic symbols displayed on communication boards or incorporated into speech-generating devices. As such, implementing AAC strategies can thus support or provide alternatives for learners with impairments in speech and language comprehension and/or expression, encompassing both spoken and written communication. However, learners who could benefit from AAC face significant challenges. The population is highly diverse, making it difficult to accurately identify and describe them. As a result, many of these learners remain ‘hidden’, a situation further exacerbated by the lack of standardised definitions, terminology and prevalence data.

In the international educational and rehabilitation literature, as well as in clinical practice, the terminology includes, but is not limited to: minimally verbal; non-speaking; non-verbal; complex communication needs (CCN); or little or no functional speech (LNFS); or the archaic and misleading ‘mute’. These terms have been operationalised differently. The term ‘minimally verbal’ has been defined as speaking fewer than 20 spontaneous novel words in a 20-min language sample (Almirall et al., 2016), while ‘non-verbal’ refers to a lack of functional communication, including the absence of consistent use of vocalisations, eye gaze and/or gestures to communicate (Franco et al., 2013). The term ‘non-verbal’ shares a similar intent with the earlier label ‘non-speaking’, which described individuals without speech (Glennen & DeCoste, 1997). ‘Non-verbal’ gained popularity as it contrasts with ‘verbal’, a term that, although related to language, is ambiguous, often implying speech in colloquial use (Alant et al., 2006). In this context, ‘non-verbal’ literally means ‘without words’, which could be interpreted as ‘without language’. Additionally, ‘non-verbal’ also implies a lack of speech.

To find a more accurate description of individuals who need or use AAC, the International Society for AAC adopted the term ‘persons with complex communication needs’ in the premier journal within the field of AAC (Alant et al., 2006). While this term was politically correct at the time and carried a strong advocacy orientation, some researchers reported that it was too broad, as it would include conditions like stuttering, which is not the focus of the AAC field. This led to a more precise definition of CCN, specifying that it refers to individuals who produce fewer than 30 intelligible words (Beukelman & Light, 2020). Some authors, however, set the bar at 15 or fewer intelligible words (Cantwell & Baker, 1985). The overly simplistic term ‘mute’ used to describe children who presented with minimal to no language comprehension, but utter non-communicative sounds (Hingtgen & Churchill, 1969), is no longer in use, as it carries negative or outdated connotations.

Notably, the terms described above have been used interchangeably in literature and practice. Ultimately, all these terms refer to individuals who cannot rely on speech to meet their communication needs, thereby representing an expressive communication disability. This highlights the lack of a standard definition or consistent terminology to describe this population – individuals who do not (or cannot) use speech – while also recognising their full range of communication abilities, rather than focusing solely on the absence of speech (Koegel et al., 2020). It is of special note that the Convention on the Rights of Persons with Disabilities (CRPD), an international human rights treaty adopted by the United Nations almost 20 years ago, recognises that communication is a basic human right for all (United Nations, 2006). Organisations such as CommunicationFIRST take this further and encourage the use of descriptive terms and not to use euphemisms such as ‘non-verbal’ and ‘CCN’; as these are factually incorrect (CommunicationFIRST, 2023). This article argues that it is not necessary to quantify the exact number of intelligible words that these individuals can produce. Instead, a qualitative approach is more appropriate, focusing on the fact that their speech is insufficient to meet their daily communication needs. Accordingly, this article will adopt the descriptive term LNFS as used by other scholars (Mophosho & Masuku, 2021; Wendelken & Williams, 2023).

It is imperative to understand that although children with LNFS have a significant communication disability, they form a heterogeneous group. These children can be of any age, from any ethnic or cultural group or any socio-economic background (Beukelman & Light, 2020). They can also experience a range of difficulties with their receptive language skills, which may manifest in difficulties following given instructions, responding to questions and even understanding stories.

Little or no functional speech is further associated with both developmental disabilities (such as autism spectrum disorder) and acquired disabilities (such as traumatic brain injury). Apart from the diagnoses that differ, so might the severity, and hence, their speech may be slightly, obviously or severely unintelligible (Andersen et al., 2010). Therefore, learners with LNFS cannot fully participate in classroom-based activities, as teaching and learning are predominantly presented using verbal communication (Bornman, 2021). Learners with LNFS present with known activity limitations and participation restrictions, of which AAC, if used appropriately, may minimise the barriers experienced (Mophosho & Masuku, 2021). As a result, these children would benefit from AAC system(s) and strategies to either supplement their poor expressive communication skills or, in other cases, provide an alternative to their natural speech (Beukelman & Light, 2020).

In line with international policies (e.g., the Convention on the Rights of the Child, which was ratified in 1995) and local legislation as captured in Chapter 2 of the Bill of Rights and in Section 29 of the Constitution of South Africa (Constitution, 1996) as well as in the subsequent South African Schools Act of 1996 (DoE, 2001; Istaryatiningtias & Daliman, 2021), all children between the ages of 7 and 15 – including those with disabilities – have the right to basic education. The limited speech of learners with LNFS typically results in poor classroom participation (Beukelman & Light, 2020; Bornman, 2021) and barriers to learning (both academically and socially). In addition to supporting Beukelman and Light’s (2020) definition of AAC, the Department of Education also highlights that AAC systems and strategies help to alleviate barriers to learning (DoE, 2001), thus making it a reasonable accommodation to ensure educational equity for these children. The DBE (2011) defined reasonable accommodations to include specialised equipment and assistive technology to support LSEN. In line with this, Mophosho and Masuku (2021) described AAC as a human rights tool, not only a receptive and expressive communication tool, but also a means to access education and achieve optimal educational outcomes. Research shows that successful AAC implementation requires teacher training (Mophosho & Masuku, 2021). When trained in AAC strategies, teachers’ perceptions of their own skills, their learners’ communication abilities and classroom inclusion improve (Ngcobo & Bornman, 2024).

One of the greatest challenges in providing services to children with LNFS in educational settings is the lack of descriptive data, which hinders effective service planning. As highlighted earlier, the unavailability of such data is attributable to, among others, the variability and fluidity in the terms used to describe the population who need and/or use AAC. For these learners, the absence of standardised tests or a unified ‘test battery’ that considers both receptive and expressive skill components (Koegel et al., 2020) means that clinicians often rely on informal assessment tools and clinical judgement. This approach is adapted from general language assessment, where SLTs have long developed custom-made screening, identification and even assessment measures (or a combination thereof) (Pascoe et al., 2010). Augmentative and alternative communication assessments are further complicated by the heterogeneity of the population. For example, how an assessment is conducted varies significantly between a child with a physical disability and a child with a cognitive disability, even though both children might need AAC. Furthermore, there are no standard tools for screening or assessing children with LNFS that are linked to specific AAC solutions (i.e., a learner with a specific score on a specific test would benefit from a specific AAC solution). To address this pressing need, this scoping review aims to systematically catalogue existing survey instruments for identifying and describing school-age children with LNFS, who could benefit from AAC. These findings can inform the development of a tool to conduct descriptive studies, providing SLTs with foundational data to guide service planning for this population.

The results of the scoping review are presented as descriptive information related to the seven included studies (e.g., author(s), year of publication, the main aim of the study and the country), the population (e.g., age, number and sex of the participants) and the study context (e.g., participant description and place of data collection) (see Table 2). An analysis of the concept (i.e., the survey instrument) described in the various studies then follows (see Table 3).

Speech-language therapists play a vital role in assessing and managing learners with LNFS in special schools (Sharma, 2021). The results from this scoping review highlight the limited availability of instruments that can be used to identify and describe learners with LNFS. Only seven studies were identified, with three originating from the US (#1, #5, #6), two from South Africa (#2, #4) and one each from Israel (#3) and Canada (#7). This scarcity may be because of several factors, including ongoing challenges in clearly defining the population of interest and selecting the most suitable methodologies for data collection. The literature reflects variation in how this population is conceptualised. Some authors focus on providing descriptive accounts (e.g., #3, #5, #7), while others attempt to quantify specific characteristics associated with the group (e.g., #1, #2, #4, #6). For instance, Sutherland et al. (2005) employed the term CCN to characterise the population more broadly. In contrast, South African studies defined participants more specifically by quantifying expressive language abilities, referring to learners as using fewer than 15 intelligible words or fewer than 30 intelligible words (Alant, 1999; Bornman & Alant, 1996). This poses a serious research challenge because of the lack of uniformity in terminology, which could lead to miscommunication, confusion and a misinterpretation of research findings (Smoktunowicz et al., 2020).

In addition to differences in how the population was defined, the studies also varied in the level of biographical detail reported. Some studies did not disclose the gender of participants (Sutherland et al., 2005), while others provided both gender information and male:female ratios (Erickson & Geist, 2016; Lillehaug et al., 2023). Moreover, there was considerable variation in the ages of participants across the included studies. Some studies reported on children as young as 18 months (e.g., #7), while most studies focused on school-aged children, with a few also including individuals up to school-leaving age (e.g., 20 years old). As noted by Heidari and colleagues (2016), researchers who omit detailed biographical information may do so because they do not perceive it as essential to their study objectives. The lack of agreement on biographical characteristics and definitional boundaries across the available studies precludes the possibility of conducting a meaningful comparison across studies. Standardisation in these areas is essential to ensure data compatibility and interpretability across different research contexts.

In addition, the findings also indicate that most of the studies presented a similar pattern in terms of investigating the learner variables when attempting to identify and describe learners who could benefit from AAC. Typically, a list of the different AAC systems, including both unaided and aided systems, was provided (Alant, 1999; Binger & Light, 2006; Erickson & Geist, 2016; Sutherland et al., 2005). No pattern was observed in terms of investigating the school performance of learners, skills and functionality, with some studies including these factors (Alant, 1999), while others did not (Sutherland et al., 2005).

Furthermore, there is no set protocol on who to use as informants for gathering descriptive data. The findings indicate that in high-income countries, the informants included agencies (#7), school principals (#3) and clinicians (SLTs) (#6). In contrast, in the low- and middle-income country (LMIC) included in the study – South Africa – teachers were used as informants (#2, #4). The rationale being that in the absence of SLTs, teachers were deemed well-positioned to identify and describe learners with communication difficulties, as well as describe learners’ functional performance.

Linked to the variation in informants is the challenge of determining appropriate data collection settings. In all the studies included in the review, data were collected either in LSEN schools (#2, #3, #4, #5, #6) or across a combination of sectors such as hospitals, preschools, rehabilitation centres and residential homes (#1, #7). These settings may have been selected based on the age range of the children studied. However, collecting data primarily in schools presents a significant limitation, as it may exclude children who are not currently enrolled in educational settings. The reasons for non-enrolment may vary; however, such children could still benefit from AAC interventions (Zhang & Holden, 2025).

Another aspect linked to who provided the information is related to the best method of collecting data. Similar to the findings noted in the review, some of the earlier descriptive studies were article-based (Alant, 1999; Bornman & Alant, 1996; Sutherland et al., 2005), while some of the later studies were online-based (Binger & Light, 2006; Erickson & Geist, 2016). In LMICs, article-based surveys are preferred over online surveys because of various factors such as limited Internet access, digital literacy, population coverage, data collection infrastructure and cultural and social factors.

The findings also indicated a variation in the time needed to complete the surveys. Some studies did not specify the time needed to complete their survey (Sutherland et al., 2005), while others were described as ‘short’ (e.g., Alant, 1999; Bornman & Alant, 1996). The literature consistently agrees that surveys should be concise; subsequently, lengthy instruments and questions can lead to respondent fatigue and incomplete responses (Ghafourifard, 2024). The findings from this review suggest that there is no set guidance in reporting response rates. Some studies presented a high response rate (#1, #2, #3, #4, #6); in contrast, some did not calculate the response rate (#5), which poses a challenge when wanting to understand the limitations of the given findings (McMillan & Schumacher, 2010).

While some insight into learners with LNFS has been gained, there remains a critical need for more robust and geographically diverse research. A key challenge is the lack of consensus on terminology, which hinders both the identification and description of this population and limits comparability across studies. In addition, decisions regarding which biographical and contextual variables to include, such as age, gender, diagnosis and educational placement, are often inconsistent, limiting the generalisability of findings. Methodological variations further compound these issues, as studies differ in their selection of participants, data collection strategies and the materials used. Establishing greater standardisation in definitions and methodologies would enhance the comparability of research outcomes and ultimately contribute to a more accurate and comprehensive understanding of individuals with LNFS, which could in turn positively impact service delivery.

Surveys used to identify and describe learners with LNFS who could benefit from AAC present with little to no uniformity. There is no standard uniformity in terms of the survey structure or even the data to be collected. Surveys are typically custom-designed to align with specific research objectives. However, biographical information and details about AAC systems learners use or require are common elements found across most of these surveys. Given their expertise in communication development and intervention, SLTs play a critical role in both designing and administering these surveys, as well as in interpreting the data to inform individualised AAC recommendations and support strategies.