Strength

сќльный гћлос a strong voice
слђбый гћлос a feeble voice
небольшћй гћлос a small voice
крљпнуть/окрљпнуть: у Ng гћлосn окрљп N's voice has grown stronger
напрягђть/напрїчь гћлосa to exert one's voice, e.g. to speak or sing with some force