Do words really matter? Well, from the Torah we learn that they most certainly do.
When G-d tells Noah to gather the animals into the Ark, he says: “From the pure (kosher) animals take seven pairs and from the animals that are not pure take two pairs.”
Notice the extra wording? Instead of simply saying “impure” the Torah says “that are not pure”. (This difference is more pronounced in the original Hebrew which has entirely different words for Pure and Impure: “Tahor” and “Tammei”).
Explains the Talmud: The Torah is not known to waste words. Often entire laws are learnt from even a single letter or word. The fact that the Torah goes to these lengths to avoid using a negative word teaches us how important it is to endeavor to speak positively whenever possible.