Sorry to nitpick, but you don’t need to be deaf to be able to read lips.
I’ve never used Faceposer, but I can tell you that lip reading is not conclusive reading. Many phonemes cannot be distinguished from eachother, because in many cases the difference in articulation is made inside the mouth and not with the lips. According to Wikipedia, only about 30, 40% of the sounds in the English language are distinguishable by sight alone. So there is some guesswork involved.
Which means Faceposer actually shouldn’t contain as much different “mouth shapes” as you would expect, because there simply aren’t different ones for every phoneme.
That said, this review states that in Half-Life 2 as Alyx spoke “her lips formed every syllable to near lip-reading standards”. Whether the reviewer has done their research or not is another story, but it sure is interesting stuff. 