In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
If one is certain that his wudu broke, he should discontinue with his Salat immediately. He should renew his wudu and repeat his Salat.[1]
If one merely has a feeling that his wudu broke, then the wudu would be regarded to be intact. The mere feeling of wudu being broken should be ignored.
The repeating of a letter, or a verse or a Tasbeeh does not invalidate the Salat.
There is no problem if those present in the room can hear the recitation of a Salat that is to be read aloud. For example, Maghrib Salat. Zuhr and Asr Salats are not to be read aloud.
If you are performing Fajr, Maghrib or Esha Salat by yourself, you may recite aloud. Accordingly there is no problem if someone hears your recitation. The recitations of Zuhr and Asr Salat have to be silent.
And Allah Ta’āla Knows Best
Mufti Saeed Ahmed Golaub
Islamic Solutions
Jamaica
References
[1]:وليس بصلاة فكان الوضوء فيه استحبابا كما في القراءة " ويكره أن يقيم على غير وضوء " لما فيه من الفصل بين الإقامة والصلاة. الهداية في شرح بداية المبتدي (1 / 44)