I think yor idea that Mary's trying to act/sound educated might be to get her father's attention is interesting. On the other hand, Mary had access to as good of books as Lizzy, who, as we have seen, could refer to Shakespeare and Gilpen at will (without being pedantic). Also, we know the girls had access to a circulating library from Ch. 14, when Mr. Collins read Fordyce instead of a novel. I tend to think it Mary's vanity that drives her reading and practicing--her "accomplishments" are a substitute for beauty remember--rather than something she takes solace in. But perhaps I am too hard on her!