Soul Marriage

To facilitate a marriage it is necessary to give a woman something of value as well as to express verbally the intent that the object is being given in order to facilitate the marriage. It is apparent from Talmudic sources that the verbal expression is an integral part of the marriage transaction. Unlike other transactions in which speaking is only necessary to make certain the intent of the parties, by marriage it forms an inherent part of the act of marriage.

Why?

Nezer Yisrael explains that the intention of marriage is to create a soul-level relationship. When Hashem created man it says ויפח באפיו נשמת חיים, He blew into his nostrils a soul of life. Onkelos renders the נשמת חיים as רוח ממלא, the ability to speak. Ergo, speech is the essential feature of the soul. Therefore in order to foster a soul-level relationship with a spouse it is necessary that it be created by means of speech, not merely by a transaction.

Furthermore he writes that when one is seeking a spouse it is important that one not get distracted by other traits of the person, wonderful as they may be. In order to have a soul level connection what is most important is the ability to communicate by means of speaking to one another. Everything else is secondary to finding someone with whom you can communicate with properly.