Question production in agrammatism: The Tree Pruning Hypothesis

Naama Friedmann*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


This study investigated question production in agrammatic aphasia, focusing on the comparison between Wh questions and yes/no questions and on the interaction between the question production deficit and language-specific properties. A total of 16 agrammatic aphasics (13 Hebrew speakers, 2 Palestinian Arabic speakers, and 1 English speaker) participated in the study, which included sentence elicitation and repetition tasks. In addition, the patients' spontaneous speech, containing 2272 utterances, was analyzed. The main findings were that Hebrew-and Arabic-speaking agrammatics encounter severe difficulties in Wh question production but retain the ability to produce yes/no questions. English-speaking agrammatics do not show this dissociation and can form neither Wh nor yes/no questions. These dissociations as well as the error pattern, are explained by reference to the Tree Pruning Hypothesis, according to which the highest nodes of the syntactic tree, which are required for Wh questions in Hebrew, Arabic, and English and for yes/no questions in English, are impaired or inaccessible in agrammatism.

Original languageEnglish
Pages (from-to)160-187
Number of pages28
JournalBrain and Language
Issue number2
StatePublished - 2002


FundersFunder number
Israel Foundation Trustees
U.S.-Israel Binational Science Foundation1997451
National Institutes of Health
National Institute on Deafness and Other Communication DisordersR01DC002984


    • Agrammatism
    • Aphasia
    • Arabic
    • Hebrew
    • Question
    • Speech production
    • Syntax
    • TPH
    • Tree pruning
    • Wh questions
    • Yes/no questions


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