Speech and the
Development of Mental
Processes in the Child

Luria and Yudovich’s experimental study of a pair of twins whose speech development was delayed, and of what changed in their thinking when it was corrected — a foundational text for the argument that language shapes mental process. First published in the USSR in 1956, translated into English by Staples Press in 1959, and issued in Penguin Education in 1971, reprinted through 1978. Edited by Joan Simon with a new introduction by James Britton. The chapters follow the twins G through psychological characterisation, the peculiarities of their speech, the experimental development of that speech, and the resulting changes in the structure of their mental activity.