Does laughing during prayer, without making a sound, invalidate the prayer?

The madhhab (definition) of the majority of scholars is that laughter does not invalidate the prayer unless two letters are formed from it. As for smiling or laughter from which two letters are not formed, it does not invalidate the prayer. Al-Nawawi transmitted Ibn al-Mundhir's consensus on the invalidity of prayer due to laughter if two letters are distinctly uttered. Ibn Hazm chose the opinion that smiling invalidates the prayer, but the correct view is that of the majority.