Short answer
On the stronger Hanafi view, a woman's voice is not awrah in itself, so she may speak to non-mahram men when there is a need, in a normal, firm tone. She should not soften her speech, and she should not sing or recite melodiously in front of them.
The preferred view, as Ibn Abidin records, is that her voice is not awrah, but anything that leads to fitnah is avoided: a soft or flirtatious tone, singing, or melodious recitation in front of non-mahram men. For this reason she does not give the adhan, recites quietly in prayer, and claps rather than saying Subhan Allah to alert the imam.
The four schools agree on this.
Explanation
Women spoke to the Prophet ﷺ, asked him questions in public, narrated hadith and taught men. Aishah taught many of the great scholars of the next generation. So ordinary speech is clearly allowed. The Quran's instruction is about the manner: do not be soft in speech, lest someone with a disease in his heart be tempted, and speak in a decent way. The four schools broadly agree on this.
In practice:
- Allowed: talking to a doctor, teacher, colleague, shopkeeper or customer; asking a question in a class; giving evidence; answering the door or the phone.
- Avoid: a soft or playful tone, flirting, long casual chats, and voice notes or calls with non-mahram men that have no need.
- Not allowed in front of non-mahram men: singing, and reciting the Quran or nasheeds in a melodious voice for them to hear.
Some Hanafi texts did describe the voice as awrah, and from this caution come several rulings in worship. A woman does not give the adhan or iqamah for men. She recites quietly in her own prayers. In congregation, if the imam makes a mistake, a man says Subhan Allah while a woman claps the back of one hand on the other, as the Prophet ﷺ taught.
A Muslim woman can and should speak up, ask, teach and work. The aim is dignity, not silence. See haya in Islam and women in Islam.
The evidence
Quran, Surah Al-Ahzaab 33:32
يَٰنِسَآءَ ٱلنَّبِىِّ لَسْتُنَّ كَأَحَدٍۢ مِّنَ ٱلنِّسَآءِ ۚ إِنِ ٱتَّقَيْتُنَّ فَلَا تَخْضَعْنَ بِٱلْقَوْلِ فَيَطْمَعَ ٱلَّذِى فِى قَلْبِهِۦ مَرَضٌۭ وَقُلْنَ قَوْلًۭا مَّعْرُوفًۭا ﴿٣٢﴾
O wives of the Prophet, you are not like anyone among women. If you fear Allah, then do not be soft in speech [to men], lest he in whose heart is disease should covet, but speak with appropriate speech.
Regulates the manner of a woman's speech with men, not speech itself.
Sahih al-Bukhari 1203
Sahih... التسبيح للرجال والتصفيق للنساء ...
"Saying Subhan Allah is for men and clapping is for women."
Shows women alerting the imam without raising their voice in congregation.
Where the ruling is recorded
- Radd al-Muhtar (Ibn Abidin), Kitab al-Salah, chapter on the conditions of prayer, covering the awrah. Her voice is not awrah on the preferred view, but softening it is forbidden.
- al-Durr al-Mukhtar, Kitab al-Salah, chapter on the adhan. A woman's adhan is disliked.
This answer is pending review by the scholars on our team. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.