1.   His voice softened as he spoke to her.

2.   His voice had softened, grown almost tender.

3.   As he said this, his voice softened and his face took on a look of total sincerity and gratitude.

4.   But she has been haunted for a year, and her voice softens as she reflects on mortality.

5.   Her voice softened and was almost lost in the echoes of the old building.

6.   His voice softened as he explained how Persian rug makers sometimes wash their creations gently in tea to soften the colors and texture.

7.   His voice softened.

8.   Then his voice softens.

9.   Her voice was softening.