The Torah teaches us to be careful with our choice of words. The choice of words used in everyday speech should be eidel (refined), and words used by the world at large to describe immoral concepts must be avoided so that they do not pass our lips at all. This is learned [1. Pesachim 3a] from the fact that the Torah is particular to choose only unblemished, clean words. When Noach was commanded to take two of each type of non-clean animal into the ark, Hashem used the five words בהמה ×שר ×œ× ×˜×”×•×¨×” – “the animal that is not clean” [2. Bereishis 7:2] rather than the two words בהמה טמ××” “the defiled animal.” Since it was possible to use a more refined term, Hashem did so, even though it meant using three extra words. Similarly, Chazal (our Sages) always choose as pure a language as possible – see Sanhedrin (68b) where the Mishnah says, דברו ×—×›×ž×™× ×‘×œ×©×•×Ÿ × ×§×™×” -“The words used by our Sages are as clean and refined as possible.”
Purity of speech is of maximum importance. It may seem to some that to guard one’s tongue and use the cleanest language possible would be an ideal way of life, fit for a world with high morals, whereas, in our day and age, when immorality and corruption gather momentum all the time, it is innappropriate to stress such a seemingly trivial matter. This is however far from correct. Hashem especially revealed the requirement of clean language just before the flood – at a time when the world was utterly corrupt – to teach us that unstead of ignoring purity of speech at such a time, it was in fact one of the most important things to strengthen. Downward trends always start with leniencies in things which poepole considered as trivial or of secondary importance. Therefore, our own tznius depends on us having a לשון × ×§×™×” – a clean and pure speech, and in our times, more than ever, keeping what we say clean and refined must a top priority.