It is very difficult to deal with shy partners in a relationship. Especially in arranged marriage, if a person is reserved and shy to talk much, it will he hectic task and they might take lot of time to gel with you and your family.
To make them feel free there are few steps. Avoid nasty remarks as they would break the partner's self esteem and confidence. Unpleasant comments will create new headaches and positive comments would make the relation better. Compliment is best factor to make your partner to talk to you.
Outing would be one more option. Taking your partner for a movie or coffee would be great idea. While having coffee discussing common interests and memorable moments makes a good conversation. And watching movie together will build a bond between each other. Being supportive during family events makes you partner happy. If your reserved person is shy to talk to others, hold their hand and introduce them to others, it could make them open up and talk something or the other.