The Brevity Rule
Comic balloons hold 2–8 words comfortably, up to 15 if the speech is in-character verbose. Past 15 the balloon dominates the panel and reads as wall-of-text. Most working comic writers keep dialogue under 8 words per balloon and split longer thoughts into multiple balloons within the same panel. The exception: a single long balloon used deliberately to feel rambly, anxious, or pedantic — but that's a special effect, not a default.
Voice Differentiation — The Single Most Important Skill
Pick any panel from a great comic, cover the speaker's name, and you should be able to identify who's speaking from the dialogue alone. This is voice. Each character has a different rhythm, vocabulary, and worldview that shows up in every line they speak. Forgettable comics have one voice across all characters (the writer's). Working comic writers build voice by giving each character a verbal tic — a sentence structure they use that others don't, a vocabulary range they stay inside, a topic they keep returning to.
Practical Voice Test
After scripting a scene, swap the speaker names randomly and re-read. If any swapped line still works for the new speaker, your voices aren't distinct enough. Voice means a line cannot be moved without breaking.
Balloon Character — Shape as Sound
Different balloon shapes signal different speech registers. Round balloon = normal speech. Jagged balloon = shouting or yelling. Scalloped/cloud balloon = internal thought or telepathy. Square balloon = narration or off-panel voice (radio, TV, voiceover). Outlined-only balloon (no fill) = whisper. Working letterers vary shape constantly to keep dialogue tonally legible; consistent round-balloon-everywhere reads as amateur. Specify balloon shape in the script — it's a writing decision, not a lettering decision.
Subtext — Saying Less Means More
Great comic dialogue rarely says what the character means directly. A character who is angry doesn't say 'I'm angry'; they make a small mean comment about an unrelated topic and let the reader infer. A character who is afraid doesn't say 'I'm afraid'; they change the subject when the threat is mentioned. Subtext is the difference between dialogue that reads as written-by-a-human and dialogue that reads as written-by-an-AI. The art carries the literal moment; dialogue is best used for the unsaid part.
Attribution — Who Speaks, Without Words
Comic dialogue doesn't use 'he said' / 'she said' attributions like prose. The balloon tail points at the speaker. If two characters share a panel and only one speaks, the tail makes it obvious. If the tail's source is off-panel, the writer marks it: 'CHARACTER (off-panel)'. Three or more balloons stacked in one panel risks attribution confusion — the eye loses track of which tail belongs to which. Keep stacked balloons clearly tailed or split the dialogue across two panels.
Dialogue vs Caption — When to Use Each
Captions (the boxed narrator text) and dialogue (the balloon character speech) do different jobs. Use caption for what the character thinks about the scene from the outside — narration, reflection, time-jumps. Use dialogue for what the character says inside the scene. Mixing them up — narrating in dialogue, dialoguing in caption — reads as off. Many modern comics drop captions entirely and use dialogue + thought-balloons only; the choice is stylistic but should be consistent within an issue.
Sound Effects (SFX) as Dialogue Adjacent
SFX aren't dialogue but they live in dialogue's space — they're the third class of words on a panel after balloon speech and caption. Treat them as dialogue from the world: lettered, sized, and weighted to carry their sound. A loud explosion's SFX is large, bold, and angular; a soft footstep's SFX is small, thin, and rounded. SFX writing is a craft of its own; working comic writers script SFX size and weight as deliberately as they script dialogue.
Dialect, Slang, and Era
Comic dialogue carries setting through word choice. A 1940s detective speaks differently from a 2026 hacker; a Brooklyn cab driver speaks differently from a Boston academic. Working comic writers research the speech patterns of their setting before scripting major dialogue scenes. Heavy-handed dialect (phonetic spelling of accents) reads as outdated and often condescending in 2026 — use vocabulary and rhythm to suggest dialect, not phonetic spelling.
Common Comic Dialogue Mistakes
Five errors that flag amateur comic dialogue: every character speaks at the same vocabulary level; balloons consistently exceed 12 words; the same balloon shape used throughout; no subtext — characters say exactly what they mean; SFX written as small balloon-bolted-on instead of composed lettering. Any one of these is forgivable; three or more in the same issue and the dialogue reads as unworked.
Writing Dialogue With AI Help
Modern AI comic generators output paneled scripts with dialogue auto-filled. The AI handles structure (panel count, balloon placement, basic attribution) well; voice differentiation less so. The strongest AI-assisted workflow: let the AI script the panels and rough dialogue, then rewrite every balloon for voice. Time-saving is real, and the voice-pass is where your craft shows.