Whoever does wudoo’ for prayer, there is nothing wrong with him speaking permissible words with his family or brothers etc. It is not haraam for him to speak certain words because of his wudoo’, rather what is haraam before wudoo’ is also haraam afterwards, such as lying, backbiting, slandering, swearing, insulting etc.
But because wudoo’ is an expiation for bad deeds, and sins are erased by it, you should try to avoid haraam things after doing it, so that you may stand before Allaah pure and clean. Muslim (244) narrated from Abu Hurayrah that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “When the Muslim or believing slave does wudoo’ and washes his face, every wrong thing that he looked at with his eyes comes out from his face with the water or with the last drop of water. When he washes his hands, every wrong thing that he did with his hands comes out from his hands with the water or with the last drop of water. When he washes his feet every wrong thing that he walked to with his feet comes out from his feet with the water or with the last drop of water, until he emerges cleansed of sin.”
And he also narrated (245) from ‘Uthmaan ibn ‘Affaan that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Whoever does wudoo’ and does wudoo’ well, his sins will emerge from his body until they even come out from beneath his fingernails.”
And Allaah knows best.