Antonyms for the phrase "talks nonsensically" can be words like coherent, logical, rational, reasonable, sensible, lucid, understandable, and intelligible. When someone communicates with clarity, precision, and relevance, they are considered to be speaking in a rational manner. The opposite of talking nonsensically is speaking with coherence and substance, conveying thoughts, and sharing opinions that make sense. When a person rambles or speaks incoherently or illogically, they can quickly lose the attention and respect of others. Therefore, the importance of speaking with clarity and coherence cannot be overemphasized, especially when communicating with colleagues, business clients, and associates.