soft s

Core Rule

The soft s refers to the letter s pronounced as /ʒ/ rather than /s/. This occurs mainly due to historical sound change and vowel influence, especially in patterns like -sure and -sual.

Articulation Guide

Place the tongue near the post‑alveolar ridge, slightly retracted; lips relaxed; vocal cords vibrate while air flows smoothly with friction.

Word Analysis

• treasurer /ˈtrɛʒərər/: intervocalic s shaped by -sure.
• usual /ˈjuːʒuəl/: s softens within -sual.
• unusual /ʌnˈjuːʒuəl/: prefix does not alter the soft s.

Pitfalls

Do not confuse /ʒ/ with /z/ or /ʃ/. Not every s+u sequence triggers the soft sound; stress and morphology matter.