The two sentences have similar meanings, but there is a subtle difference between them. The first sentence, "Her manners and language are too gross for a lady," implies that the person's manners and language are not appropriate for a lady, suggesting that the person is not behaving as they should. The second sentence, "Her manners and language are too gross as a lady," implies that the person's behavior is inappropriate even for someone who is considered a lady. In other words, the sentence suggests that the person is not acting in accordance with societal expectations for someone of their gender and social status. Overall, both sentences convey a similar message, but the second sentence implies a slightly stronger condemnation of the person's behavior.