As far as woman matters are concerned, decency and modesty should be observed. Islam acknowledged the natural inclination of both man and woman towards one another and therefore, it stressed on preventing every way that might give rise to temptation and seduction.

Turning to this question, it is permissible for a woman to speak in the presence of non-mahram (marriageable) men, provided her speech is straightforward and serious and free of softness, temptation or provocation in her voice. Woman’s voice is not ‘Awrah (i.e. should not be heard be non-mahram men) according to the correct scholarly view. This is because women used to speak to the Prophet (peace and blessings of Allah be upon him) and ask him questions, and they used to speak to the Sahabah (companions of the Prophet) about their needs, and they were not denounced for doing so. Rather they were forbidden to be soft in speech as Allah says: 

(If you keep your duty (to Allah), then be not soft of speech, lest he in whose heart is a disease aspires (to you), but utter customary speech.)Al-Ahzab (33:23)

Al-Qurtubi (may Allah have mercy on him) said in his Tafsir (exegesis) of this verse: “Allah commanded them to make their speech serious and straightforward, and their posture and gestures should not convey wrong ideas, as the Arab women used to do when speaking to men, by making the voice soft and gentle, like the speech of immoral women and prostitutes; He forbade them to do that.”

May Allah grant all of us success