Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.  If you mean by "cheap and vulgar words" those which are related to sexual intercourse this is a part of enjoying ones spouse, thus it is lawful.If you mean, filthy language then it is not allowed since a Muslim does not use bad words in any circumstances.  The Prophet (Sallallahu Alaihi wa Sallam) said: "A believer does not taunt, curse, abuse or talk indecently".  [Ahmad and al-Tirmizi, Sheikh al-Albani graded it is sound] Allah knows best. (Source: islam_web) Classified in Women and Family > Marital Rights