Spiritual communication stands for the spiritual commitment you share with each other through the Sacrament of Matrimony. Pray together during those sometimes long periods of abstinence that are difficult. Remember that marriage is not just two people living together. It is a husband, wife and God. Periodic abstinence is a wonderful time to develop a strong spiritual relationship with one's spouse.
Physical communication means employing non-sexual activity during times of abstaining.
Use this time to 'get to know each other better', and discover things that you both enjoy together. Some examples would be mastering the technique of giving a good massage or back rub, dancing to some romantic music, preparing a late night gourmet dinner after the little ones are tucked in, enjoying a fun game of Monopoly together, or just falling asleep in each other's arms. Be sure to throw in plenty of good ol' platonic hugging. Intellectual communication involves sharing the intellectual areas you have in common with each other. This could be reading poetry to each other, working on a joint research project, doing some Bible study together, watching and old movie, sharing some intimate hopes and dreams, or tenderly recalling the first days of your courtship.