enunciate
To speak words very clearly so each sound is heard.
To enunciate means to pronounce words clearly and distinctly, making each sound crisp and easy to understand. When you enunciate, you don't mumble or slur your words together. Instead, you speak carefully, giving each syllable its proper shape.
Teachers often remind students to enunciate when giving presentations, because even brilliant ideas get lost if the audience can't understand what you're saying. Actors practice enunciating so every person in a theater, even in the back row, can follow the dialogue. If someone tells you to enunciate, they're asking you to speak more clearly, not necessarily louder.
Good enunciation means paying attention to the endings of words (saying “going” instead of “goin'”), separating words that might run together (“Did you eat?” rather than “D'jeet?”), and giving consonants their full value. When you're nervous or excited, words sometimes tumble out too quickly. Taking a breath and enunciating helps your message land exactly as you intended.