What is the ruling on offering Tahajjud (optional late night Prayer) and the Witr (Prayer with an odd number of units) at home in months other than Ramadan with a loud voice reciting Taslim (salutation of peace ending the Prayer) once in the Witr?
it is better in Tahajjud to recite out loud.
it is permissible to offer an odd number of Rak`ahs (units of Prayer), whether five, seven or nine. A person should pronounce Taslim only in (Part No. 7; Page No. 229) the final Rak`ah, as it was narrated from
Um Salamah (may Allah be pleased with her) that she said,
The Messenger of Allah (peace be upon him) used to offer the Witr with seven or five (Rak`ahs) without separating between them with Taslim or any speech.
However, it is better to offer the optional night Salah (Prayer) two Rak`ahs at a time, while pronouncing Taslim after each pair, and offer one Rak`ah of Witr, as it was authentically reported in the Two Sahih (authentic) Books of Hadith (i.e. Al-Bukhari and Muslim) in the Hadith narrated by
Ibn `Umar (may Allah be pleased with him), from the Prophet (peace be upon him) that he said,
The optional Salah during the night should be pairs of Rak`ahs, but if you fear the morning is approaching, they should offer one Rak`ah, which will make their Salah an odd number of Rak`ahs.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.