"Every religion has a distinct moral call and the moral call of Islam is haya." [Hadith Bayhaqi]
Haya is an all-encompassing Islamic concept that includes modesty, decency, and inhibition against sin. It is an inner feeling. A state of mind that reflects itself in myriad ways. Among other things, it shows itself in the language one uses.
How should one communicate about morally sensitive and delicate subjects? Anyone can be crude, explicit, and vulgar. But Islam civilizes this aspect of our life also and teaches us to be refined, subtle, and indirect. As a result, the language of Islamic societies has been the language of haya. They do not talk about some subjects, (not publicly at least), not because of ignorance, but because they know. When there is need to talk about sensitive subjects, they are mentioned in a language that is as fully clothed as decent men and women should be.