Speech/Language Impairment or Specific Learning Disability? Examining the Usage of Educational Categories

Abstract

Purpose: Developmental language disorder (DLD) is a lifelong condition that when impacting educational performance is identified and serviced through U.S. schools as outlined in the Individuals with Disabilities Education Act. A few examples of educational categories that refer to DLD are (a) speech or language impairment (S/LI) and (b) specific learning disability (SLD). In this research note, we aim to examine trends in how these categories are assigned.

Method: We analyzed publicly available data released by the U.S. Department of Education from six school years between 2010 and 2020. We examined the use of S/LI and SLD categories across students of different ages at the U.S. national and state levels.

Results: We present a trend in which younger students tend to be identified with the S/LI category, whereas older students tend to be identified with the SLD category. This trend is evident in all 6 years of data analyzed at the national level, and in 49 of 50 states.

Conclusions: We discuss these findings in the context of research on language disorders to explain this trend. We highlight the potential damaging effects of using inconsistent terminology, including affecting the services for which students with DLD qualify and causing confusion for their parents and educators.

Figure 1.

Line plot of example data (Table 2) to demonstrate calculation of age-of-shift using x-value of the intersection. Blue = speech or language impairment (S/LI); orange = specific learning disability (SLD).

Figure 2.

Number of children in the United States (states, territories, and freely associated states) serviced under the Individuals with Disabilities Education Act with speech or language impairment (S/LI; blue) and specific learning disability (SLD; orange) by age for the 2010–2011, 2011–2012, 2016–2017, 2017–2018, 2018–2019, and 2019–2020 school years.

Figure 3.

A U.S. map showing the proportion of children in the 50 states serviced under the Individuals with Disabilities Education Act with speech or language impairment (S/LI; blue) and specific learning disability (SLD; orange) by age for the 2011–2012 school year. Dotted lines indicate the intersection of the blue and orange lines (if one exists). The age (x-value) of this shift is denoted. Figure generated with helper code from nandeshwar.info.

Figure 4.

Smoothed predictive curves generated by a generalized additive model, using smoothed age as a predictor of speech or language impairment (S/LI) identification (blue, left) and specific learning disability (SLD) identification (orange, right). Data points depict the raw data, which is the proportion of children with a given label in a single state.

Figure 5.

Distribution of the age at which proportion of speech or language impairment (S/LI) becomes less than proportion of specific learning disability (SLD). (A) Box plot indicates median (dark line), with each dot representing an individual state's age of shift. (B) Density histogram of the distribution of ages of shift, mean indicated by dotted line.