Is it permissible for a woman to pronounce the Adhan (Call to Prayer)?
Is her voice considered `Awrah (something that should be hidden in public) or not?
A woman should not pronounce Adhan according to the most authentic opinions of scholars, for this did not happen either in the time of the Prophet (peace be upon him) or the Rightly Guided Caliphs (may Allah be pleased with them).
The voice of women is not always `Awrah, for women used to ask the Prophet and the Rightly Guided Caliphs (may Allah be pleased with them) and other Muslim rulers who followed them about issues in Islam. Women also used to greet non-Mahram (marriageable) men and reply to their greetings at these times. None of the scholars of Islam has ever disputed this. However, it is impermissible for women to be soft in speech (with non-Mahram men) for Allah (Exalted be He) says:
O wives of the Prophet! You are not like any other women. If you keep your duty (to Allâh), then be not soft in speech, lest he in whose heart is a disease (of hypocrisy, or evil desire for adultery) should be moved with desire, but speak in an honourable manner.
This is because the way she speaks may seduce men and lead them into Fitnah (temptation), as indicated in the Ayah mentioned above. (Part No. 6; Page No. 83) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.