I
verb
BAD : Students should feel able to voice out their opinions.
GOOD : Students should feel able to voice their opinions.
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voice your feelings and opinions (WITHOUT out ): 'I'm not just voicing my own opinions - we all feel the same.' 'Whenever one of us voices the slightest disapproval, the chairman takes offence.'
II
noun
BAD : 'You're late!' he said with an angry voice.
GOOD : 'You're late!' he said in an angry voice.
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in a loud/deep/sad etc voice (NOT with ): 'She spoke in such a soft voice that we couldn't hear anything.'
Compare: 'She speaks with a strong accent.'