The power of speech goes far beyond the simple meaning of words. True communication is measured by a person's ability to shape their words to fit reality, to connect with others, and to align with the Creator. A deep contrast exists between the way honest people speak, which builds harmony, and the way wicked people communicate, which only spreads destruction and conflict.
The primary approach among commentators is that righteous individuals know exactly how to speak pleasantly. They choose good words that calm others, bring comfort, and create peace and agreement in society [רש״י, רלב״ג, ביאור שטיינזלץ, אמרי דעת]. At the same time, they use this exact same skill to please God [רש״י, מצודת דוד]. On a deeper level, this is not merely a social talent. It is a clear mental and spiritual understanding of God's will, the Torah, and natural wisdom, which they use to carefully guide their words [רלב״ג, מלבי״ם, עמנואל הרומי]. They possess a clear, absolute grasp of wisdom [מלבי״ם] and simply know how to speak effectively [אבן עזרא].
In sharp contrast, wicked individuals are defined by speech that constantly twists reality. Their words are the exact opposite of truth, honesty, and wisdom [רלב״ג, מלבי״ם, עמנואל הרומי]. While a good person looks for common ground and agreement, a wicked person does not care about what others want. They argue against every opinion, stir up anger, and offer no comfort to anyone [רלב״ג, ביאור שטיינזלץ, אמרי דעת]. Furthermore, the concept of knowing how to speak applies to them as well, but in a entirely negative way. They are deeply familiar with how to constantly twist and overturn God's word [מצודת דוד, אבן עזרא].
A subtle physical distinction in how speech is produced highlights this divide. A righteous person needs only a slight movement of the lips to pray to God and receive an answer, even when it is not a time of divine favor. Conversely, a wicked person can open their mouth wide in prayer but will achieve the exact opposite result, angering God even during a time of divine favor [אלשיך]. Ultimately, the mouth is designed to be a tool for sharing wisdom, yet the wicked choose to use it to express behaviors that completely oppose the path of wisdom [מלבי״ם].