Leiter devised an experimental edition of the test in 1929 to assess the intelligence of those with hearing or speech impairment and with non English speaking examinees.
"[1] A remarkable feature of the Leiter scale is that it can be administered completely without the use of oral language, including instructions, and requires no verbal response from the participant.
[1] This includes children with any of these features: Non native speaking, autism, traumatic brain injury, speech impairment, and hearing problems.
However, it is also used by researchers, and also very frequently by clinicians who assess the "intellectual function of children with pervasive developmental disorders.
"[3] The Leiter-3 was normed and validated with a diverse group, representative of the 2008 updated U.S. census, including a number of special groups, including those with speech impairments, deaf or hard-of-hearing, motor delays, traumatic brain injuries, intellectual delays, ADHD, giftedness, learning disabilities, autism spectrum disorder, and English as a Second Language.