On his Sentire cum Ecclesia blog, David Schutz raises the problem of difficult-to-pronounce liturgical texts. My sympathy to all Church lispers and those that have trouble getting their tongue around Church language. Difficult as it may be, advantages flow to those who persistently conquer recalcitrant texts. Admiration for anyone who can proclaim the tongue twisting genealogy of Jesus correctly is unbounded.
Like David, I too battled a childhood lisp for many years. I was cured by 1. my grandfather teaching me to whistle forwards instead of backwards, 2. being taught to "bubble" underwater by a cousin, and 3. singing many rhythmic, slow, mysterious hymns with unpronounceable texts.
My Cathedral community invariably produces a communal mumble at the word "consubstantial" in the new ICEL translation of the Nicene Creed. Singing the Creed would fix it.