Assalaamu alaykum. If a person says in prayer while sitting between the two sujoods "rabbifirlii" instead of "rabbighfirlii" Or if he makes mistakes in some other parts of the prayer. What should he do? Can he just repeat the word? If a person stammers or loses his voice during the prayer and has to take air, for example if he says: "Alham... Alhamdulillahi rabbil'aalamiin - and then continues normally. Or "atta... Attahiyyaatu lillahi - and then continues normally. Or when saying the final tasliim "as.... Assalaamu alaykum wa rahmatullah". What should he do?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

In all the situations which you mentioned in the question, if the praying person makes a mistake in pronouncing a word or he stammers, for example, then he should repeat the word correctly as it should be pronounced and he is not required to do anything after having uttered it as it should be uttered.

Allaah Knows best.