sion voicing

Core Rule

Rule 46: sion voicing explains that -sion is commonly pronounced /ʒən/ in English. The letter s becomes voiced, shifting from /s/ to /ʒ/, typically when sion follows a vowel. This reflects English phonological economy, favoring smoother airflow.

Articulation Guide

For /ʒ/, place the tongue close to the post-alveolar region without contact. Lips are slightly rounded, airflow is continuous, and the vocal cords vibrate, unlike the voiceless /ʃ/.

Word Analysis

• composition → /ˌkɒmpəˈzɪʒən/
• disposition → /ˌdɪspəˈzɪʒən/
• easily → /ˈiːzɪli/, showing intervocalic s → /z/, the same voicing principle.

Pitfalls

Avoid reading -sion as /sən/ or /ʃən/ without checking the vowel context that triggers voicing.