Effects of video based training on spoken and signed language acquisition by students with mental retardation.
Live modeling plus video beats video alone when teaching signs to students with intellectual disability.
01Research in Context
What this study did
The team tested three ways to teach new words to students with intellectual disability.
One group watched a video that showed a woman speaking and signing the word.
Another group got the same video plus a live therapist who repeated the word.
A third group worked only with the therapist and no video.
Each student had four 15-minute sessions per week for six weeks.
The kids were tested on how well they could say or sign the new words.
What they found
All three groups learned to say the new words.
Kids who had the live therapist produced more correct signs.
Video alone helped speech, but it fell short for sign language.
No group got better at understanding the words they heard or saw.
How this fits with other research
Logan et al. (2000) and Sanders et al. (1989) also show that pictures can slow learning for students with ID.
Their reading and sound-blending studies found text-only or verbal-only works faster.
Together these four papers warn: extra visuals may block language when kids already struggle.
Milhem-Midlej et al. (2025) pushes the idea forward.
They used short video clips to teach job steps to older adults with ID.
Half of them kept the skill after the clips were removed, showing video can work if you add enough practice.
Why it matters
If you run sign-language lessons, pair the tablet with a live model.
Let the student watch the clip once, then immediately imitate you.
Check receptive skills separately—seeing and saying a sign does not mean the child understands it.
This small tweak saves weeks of stalled progress.
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02At a glance
03Original abstract
The purpose of this study was to assess the effects of video presentations on the acquisition of both spoken and manually signed lexical items by students with mental retardation. A 10-lesson curriculum in which lexical items were introduced and reviewed by one of three pedagogical methods (therapist only, therapist plus video, or video only) was implemented over a four week period. Pretest and posttest measures of expressive and receptive vocabulary of 35 students with mental retardation revealed that all three methods resulted in significant increases in both spoken and manual sign production of the targeted lexical items compared to control items which were not taught. The therapist only and therapist plus video methods yielded significantly higher sign production scores than the video only method. Receptive vocabulary was not significantly improved by the intervention.
Research in developmental disabilities, 1990 · doi:10.1016/0891-4222(90)90013-x