Because of Plato we often assume that true moral development can only happen through endless conversations. But we obviously pick up an enormous amount of information from other people when we are near them - even if they don't say a word. We can learn a lot from other people just from doing simple things together with them such as cooking a meal or cleaning up the house.
"To instill a mind with honorable ideas, and to recall to rectitude those who are wavering and prone to do wrong, nothing is more effective than good men’s company. When they are seen and heard frequently, their influence is gradually internalized and acquires the force of precepts. An actual encounter with the wise is, of course, beneficial, and one can get some benefit from a great man even if he is silent. Just how this happens would be hard for me to tell you, but I am sure that it has happened. As Phaedo says,
"There are some tiny creatures whose attacks are so miniscule and insidious that we don’t even feel them when they bite us. Their bite is marked by a swelling, but even the swelling itself shows no wound."
The same will happen to you in associating with men who are wise. You will not realize how or when it helps you, but you will realize that it has."
- Seneca, Letters 94.40-41