Private speech is a cognitive tool to guide thinking and behavior, yet its regulatory use in atypical development remains equivocal. This study investigated the influence of task difficulty on private speech in preschool children with attention or language difficulties. Measures of private speech use, form and content were obtained while 52 typically developing and 25 developmentally at-risk three- to four-year-old children completed Duplo construction and card sort tasks, each comprising two levels of challenge. In line with previous research, developmentally at-risk children used less internalized private speech than typically developing peers. However, both typically developing and at-risk children demonstrated a similar regulatory private speech response to difficulty with no systematic evidence of group difference. This was captured by an increase in all utterances, reduced private speech internalization, and more frequent forethought and self-reflective content. Results support the hypothesis of delayed private speech internalization but not regulatory deviance in atypical development.

Self-directed speech is considered an important developmental achievement as a self-regulatory mediator of thinking and behavior. Atypical self-directed speech is often implicated in the self-regulatory challenges characteristic of children with neurodevelopmental disorders. A growing body of evidence provides snapshots across age-levels and diagnoses, often presenting conflicting results. This systematic review is undertaken to impose clarity on the nature, extent, and self-regulatory implications of self-directed speech interruption in children with developmental language disorder (DLD), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD).

A rigorous search process of relevant databases (i.e., PsychInfo, PubMed, CINAHL, ERIC) uncovered 19 relevant peer-reviewed articles that investigate self-directed speech in children with neurodevelopmental disorders. Consistent across the research, children with DLD, ASD, and ADHD present with differential development and use of self-directed speech.

In its synthesis of findings, this systematic review clearly explicates the differential ontogenesis of self-directed speech in neurodevelopmental disorders and interprets the self-regulatory implications for children with DLD, ASD, and ADHD. Furthermore, the review spotlights important future research directions to better understand the mechanistic relationship between self-directed speech and self-regulation.

Research into human communication has been grouped under two traditions: referential and sociolinguistic. The study of a communication behavior simultaneously from both paradigms appears to be absent. Basically, this paper analyzes the use of private and social speech, through both a referential task (Word Pairs) and a naturalistic dyadic setting (Lego-set) administered to a sample of 64 children from grades 3 and 5. All children, of 8 and 10 years of age, used speech that was not adapted to the decoder, and thus ineffective for interpersonal communication, in both referential and sociolinguistic communication. Pairs of high-skill referential encoders used significantly more task-relevant social speech, that is, cognitively more complex, than did low-skill dyads in the naturalistic context. High-skill referential encoder dyads showed a trend to produce more inaudible private speech than did low-skill ones during spontaneous communication. Gender did not affect the results.

The paper presents the current state of the art of research identifying the neurophysiological and neuroanatomical substrates of private speech, both in typical and clinical (or atypical) populations. First, it briefly describes the evolution of private speech research, which goes from classic traditions as the naturalistic and referential paradigms to the neurocognitive approach. An overview of the neurophysiological (e.g., event-related potentials or ERPs) and neuroimaging techniques (e.g., functional magnetic resonance imaging or fMRI) is also presented. The next three sections review empirical works about the neurocognitive basis of private speech, across three groups of techniques: ERPs; fMRI/MRI; and other neuroimaging techniques (positron emission tomography [PET], magnetoencephalogram [MEG], and repetitive transcranial magnetic stimulation [rTMS]). Such neurocognitive research analyzes the neural activity of individuals during a variety of task settings, including spontaneous and instructed overt and inner private speech use, subvocal verbalizations, and silent and overt reading. The fifth section focuses on electrophysiological and neuroimaging studies of private speech in atypical populations, for example: schizophrenia, pure alexia, hearing impairment, blindness, social phobia, alexithymia, Parkinson, and multiple sclerosis. The neurocognitive study of the various forms of private speech appears to be very promising in the understanding of these pathologies. Lastly, the advances and new challenges in the field are discussed.

The purpose of this study was to perform a sequential analysis of private and social speech in children's dyadic communication. To investigate the communication patterns, a category system was applied to the communication of 64 paired third (M = 8 years and 8 months) and fifth (M = 10 years and 8 months) graders, while playing with a Lego-set (construction material). The results revealed that: (a) at both grades, when one child addresses the other child about the task, it is highly probable that the latter will address the first child immediately afterwards and will adapt to task-related semantic content; (b) at both grades, children's private speech about the task stops them from communicating a task-related production to their partner immediately afterwards; (c) at third grade, task-relevant private speech favors the prolongation of the break in interpersonal communication and the use of inner speech by both children; and (d) at fifth grade, children are more able to distinguish private speech from social speech than at third grade.

The purpose of the present study was to explore patterns of mother–child interaction, children's private speech use, and behavioral self-regulation among a sample of preschool children identified by their preschool teachers as evidencing behavior problems. Forty preschoolers were classified into two groups (behaviorally at-risk and a matched comparison group) on the basis of teacher ratings of impulsivity, inattention, and hyperactivity. Children completed a magnet board puzzle task once in collaboration with their mother and once individually, and maternal and child speech and behavior were coded from videotapes. Although there were no group differences in children's behavior or speech during the collaborative session, nor were there differences in children's individual task performance or on-task attention, mother–child interaction involving behaviorally at-risk children was characterized by more other-regulation, negative control, less praise, and less physical withdrawal over time, compared to interactions involving comparison children. Behaviorally at-risk children, compared to controls, used more overt, task-relevant private speech during individual problem solving. Partially internalized private speech use among at-risk preschoolers was positively associated with task performance. Group differences rather than similarities prevailed in terms of the relations between maternal behavior, child speech, and child performance.