Vol. 15 (2026)

Research Articles

Comprehension May not Occur: Issues of Modal Verb Ambiguity in Arizona and Utah State Jury Instructions

Published 13.04.2026

  • Iia Vlasova
    • ,
  • Alexander Holmberg

Iia Vlasova
Northern Arizona University

Alexander Holmberg


Abstract

Jury instructions play a crucial role in the U.S. criminal justice system, yet the complexity of legal language can present challenges for juror comprehension. Previous research efforts within both legal and linguistic communities have aimed to improve the comprehensibility of jury instructions for jurors, who often lack extensive legal knowledge. This past research has highlighted the effectiveness of including linguistic features such as active sentences, reduced legal terminology, and increased use of modal verbs in improving jury instruction comprehension. The present study further investigates modal verb usage in jury instructions. The multiple possible interpretations of modal verbs could result in ambiguous meanings within jury instructions, a factor that has not been fully addressed in previous recommendations for enhancing jury instruction comprehension through modal verb use. Utilizing corpus linguistic analyses, the study examines civil jury instructions from Utah and Arizona. Frequency analysis of modal verbs in these instructions was carried out to establish general usage patterns of specific modal verbs within the two sets of jury instructions. Additionally, an investigation into instances of potential ambiguity was conducted using an adapted categorization of modal verb functions based on Biber et al.'s (2007) framework. Results indicate that among the nine primary modal verbs examined, instances of potential ambiguity are limited to the modal verbs may and can –specifically, the negated forms of these modal verbs. Based on these findings, we propose recommendations for slight adjustments to Arizona and Utah jury instructions to enhance clarity in modal verb usage. Potential suggestions include replacing ambiguous modal verbs with less ambiguous modal verbs, incorporating clarifying adverbial phrases or clauses, and utilizing more degree adverbs and adjectives to aid juror comprehension.

Cite as: Vlasova & Holmberg, JLL 15 (2026), 29–57, DOI: 10.14762/jll.2026.29

Keywords

modal verbs, jury instructions ambiguity, forensic linguistics, corpus linguistics, linguistics and law, plain language movement

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