The causes of LLE in otherwise healthy children are not known. However, several variables are thought to play a role.
Based on research comparing late talkers with typically developing peers on variables linked with language development, a number of risk factors for LLE have been proposed, including:
- gender—boys are at higher risk for LLE than girls (Horwitz et al., 2003; Klee et al., 1998; Rescorla, 1989; Rescorla & Achenbach, 2002; Rescorla & Alley, 2001);
- motor development—late talkers were found to have delayed motor development (in the absence of disorders or syndromes associated with motor delays) when compared with typically developing children (Klee et al., 1998; Rescorla & Alley, 2001);
- birth status—children born at less than 85% of their optimum birth weight or earlier than 37 weeks gestation were found to be at higher risk for LLE (Zubrick et al., 2007);
- early language development—language abilities at 12 months appear to be one of the better predictors of communication skills at 2 years (Reilly et al., 2007).
- family history—late talkers are more likely to have a parent with a history of LLE (Ellis Weismer, Murray-Branch, & Miller, 1994; Paul, 1991; Rescorla & Schwartz, 1990);
- presence of siblings—late talkers are less likely than children without LLE to be an only child; these findings may reflect decreased maternal resources available to the child (Zubrick et al., 2007);
- mother's education and SES of the family—lower maternal education and lower SES of the family are associated with higher risk for LLE (see Zubrick et al., 2007); maternal education and family SES are thought to be related to the amount of support (resources) available to the child for language learning (Hoff-Ginsberg, 1994; Wells, 1985).
Early identification and intervention can mitigate the impact of risk factors (Guralnick, 1997, 1998; National Research Council, 2001; Thelin & Fussner, 2005). Therefore, it is important for speech-language pathologists to recognize these risk factors when identifying LLE and considering service delivery options.
The National Joint Committee on Learning Disabilities (NJCLD; 2007) suggests a number of protective factors that may buffer children and families from factors that place them at risk for later language and learning problems. These include:
- access to pre-, peri-, and postnatal care;
- learning opportunities, such as
- exposure to rich and varied vocabulary, syntax, and discourse patterns;
- responsive learning environments that are sensitive to cultural and linguistic backgrounds;
- access to printed materials;
- involvement in structured and unstructured individual/group play interactions and conversations;
- engagement in gross and fine motor activities;
- access to communication supports and services as needed.
See Shonkoff and Phillips (2000) [PDF] for more information about the nature of early development and the role of early experiences.