The reason for this, he goes on, is that speech is the essence of emunah. [Now that I think about it, speech is the defining characteristic of what Mankind is. (the targum translates Adam's spirit as a 'speaking spirit') So, Man, the only creature with free will, ie. the ability to willfully defy HaShem, is the only one who can have true emunah, and truly call out to HaShem.]
Which leads me to understand something else. If simply speaking against emunah so deeply harms one's emunah, simple speech in support of emunah must work unbelievable healing of one's emunah.
[Maybe this is the basis of Rebbe Nachman's foundational point of regular hitbodedut.] Here too we see any speaking of or with emunah is a boon with which to fill any otherwise wasted time one may have.