Tools of Characterization
Each of the characters in Anna Karenina is fleshed out in part by the actions they commit. This is particularly true in Oblonsky's case, where his good intentions and apparent repentance are belied by his continued philandering, revealing his incapacity for keeping his word. The man says one thing and does another. Vronsky, in contrast, shows a clear deference to Anna's wishes by rushing home every time she calls him back. Dolly displays her loyalty and friendship to Anna by flouting societal convention with her visit to Anna. Princess Betsy, for all she talks of a dear friendship with Anna, refuses to hang out with her once she becomes a social outcast.
This actually occurs fairly rarely in Anna Karenina, as Tolstoy tends to be subtle. Occasionally, however, he does give us information straight out, as for example with Vronsky: "He not only disliked family life, but a family, and especially a husband was, in accordance with the views general in the bachelor world in which he lived, conceived as something alien, repellant, and, above all, ridiculous" (1.16.5).
The families and childhoods of central characters in Anna Karenina can illuminate certain aspects of personality. Vronsky's relationship to his mother seems to be fake. Countess Vronsky is known for having slept around and his dad is described by Levin as a man who climbed up by intrigue. This lack of a family life as a child, we hypothesize, is why Vronsky has such an intense dislike of it as an adult. When we first meet him, it is clear that Vronsky has no intentions of marriage, which reflects a disrespect for the traditional, pure, and virtuous values that the Shcherbatsky family and Levin uphold.
Ever since his mother died, Levin has upheld a certain vision of womanhood in his heart to which he wants Kitty to conform. His mother-in-law, by the way, isn't so pleased that Levin refuses to call her maman. This refusal stems from the reverence with which Levin views his own mother. Levin's view of family as an institution of paramount importance reflects his character's conflict with the dominant social mores of the day as exemplified by Oblonsky, who views marriage with indifference or annoyance.
Anna had an aunt who got her involved with Karenin in the first place, and she has another aunt (Princess Barbara) who freeloads off of everyone. Because Anna fails to receive love from Karenin, she transfers all her love to Seryozha. For some reason, in her second family, Anna loves Vronsky wholeheartedly but can't summon up any real love for the child she has with him. Other than that, Anna also has a brother and sister-in-law who adore her. Bottom line: Anna's family life makes it clear that she has a lot of love to give but not many people who can receive it.
Thoughts and Opinions
Did you notice all those long debates about russification and the emancipation of women and the value of the common good? We get a lot of characters voicing their opinions. Levin is characterized by this method more than anyone else in Anna Karenina. His opinions – on farming, God, what kind of woman he should marry – change often. But the importance of certain ideas to him – and the unimportance of political elections – shows his values.
Speech and Dialogue: French vs. Russian
If the characters in Anna Karenina are Russian, then why do they speak French? We get into the whys and wherefores of this in Levin's "Character Analysis," so here, we're going to focus on when French is used strategically in the novel. The aristocrats' knowledge of French comes in handy when they want to hide something from their servants. It's also worth noting that a lot of the most hypocritical characters of the novel use a lot of French, including Countess Lydia and Countess Vronsky. For more on why this might be, again — see our "Character Analysis" of Levin.
Second, the same words in different languages carry different connotations. For a while, Vronsky speaks to Anna only in French, in order to avoid having to use the Russian word for "you." If he spoke in Russian, he would have to choose between an impossibly cold, formal version of the word or an impossibly intimate version. When your relationship with someone is ambiguous, it's better to just speak in French and not have to deal with it.