It is truth that Christ gives no commandment against saying a four letter word, however - he does have plenty to say about language and its ability to defile:

After accusing the Pharisees of (essentially) saying one thing and doing the other he states...

"Listen to me, all of you, and understand: there is nothing outside a person that by going in can defile, but the things that come out are what defile." (Mark 7:14-15)

Matthew is a little more specific (as he is apt to be) in his rendition:

"Do you not see that whatever goes into the mouth enters the stomach, and goes out into the sewer? But what comes out of the mouth proceeds from the heart, and this is what defiles. For out of the heart comes evil intentions, murder, adultry, fornication, theft, false witness, slander. These are what defile a person, but to eat with unwashed hands does not defile." (Matthew 15:17-20)

One of the most important aspects of Jesus' teaching is his desire to abolish previous notions of purity laws and instigate a form of internal purity that surpasses the laws of Leviticus and Deuteronomy.

Taken in that sense, especially when coupled with the fact that cursing has an almost wholly negative connotation in the Gospels (Mark 14:71 is an excellent example - in order to prove his denial of Jesus, Peter resorts to cursing and swearing), a reading can be formed by which any language that pollutes (which many would agree includes not only the sort of false witnessing/lies/slander that are involved in the Monica Lewinsky example above but also common "foul" language) is seen as a loss of purity of person.

Does Jesus love you less? That's neither my concern nor my problem.