How to Add Voices to a Twine Interactive Fiction Game

Twine is one of the friendliest ways to build interactive fiction: you write passages, link choices, and publish a playable HTML file. What Twine does not do is talk. If you want your characters to actually speak, or a narrator to read a passage aloud, you have to bring the audio in yourself. This guide walks through generating voice clips for a Twine story and wiring them into your passages so the right line plays at the right moment.

Here is the honest boundary up front: AudioProducer makes the audio files. You download finished MP3s and embed them in your own Twine project. AudioProducer is not a game engine and does not host or build your game, so every step below that touches Twine happens in the Twine editor on your machine, not on our side.

What you need before you start

A working Twine story is the only hard prerequisite. Twine ships with a few story formats, and the audio approach differs slightly between them:

• Harlowe is the default format. It has no built-in audio macro, so you drop in a small chunk of HTML plus a line of JavaScript to play sounds.
• SugarCube has a real audio subsystem with macros like <<audio>> and a playlist manager, so it is the smoothest path if you plan to use a lot of sound.
• Harlowe or SugarCube in the browser IDE both let you reference files by relative path once you publish to a folder.

You do not need to decide the whole sound design first. Start with one or two spoken lines, get the wiring working, then scale up.

Step 1: Write out the lines you want voiced

Before generating anything, make a short script of exactly which text becomes audio. In interactive fiction the natural unit is the passage, so a simple approach is one clip per passage of narration, plus separate clips for individual character lines you want spoken in a distinct voice. List them plainly: the passage name, the speaker, and the text. This list is what you will paste into AudioProducer, and it doubles as your file-naming plan later.

Keep each clip focused. A single character's line, or one paragraph of narration, is easier to trigger and swap than a two-minute block that spans several choices.

Step 2: Generate the voice clips in AudioProducer

Open AudioProducer and paste in the text for a passage or a line. Assign a voice, and if several characters speak, give each one its own voice so the player can tell them apart by ear. Our multi-voice handling is built for exactly this: a cast of distinct speakers in a single story rather than one flat narrator. If you want guidance on casting, how to choose AI voices for characters covers matching a voice to a personality, and giving each character a different voice goes deeper on keeping a cast consistent across a long project.

Generate the audio, then export and download the MP3. Do this for each line on your list. AudioProducer hands you finished files; from here everything happens inside Twine.

A note on the free tier and quota: AudioProducer works on a single words-per-month model. You get 1,200 words free with no card, and paid plans start from $39.99 per month. For a text-heavy branching game, generate the audio for the passages you have finalized rather than every draft variation, so you are not spending words on lines you may still rewrite.

Step 3: Organize your audio folder

Twine plays audio by referencing a file path, so a tidy folder saves a lot of debugging. Create an audio folder next to where you publish your story and name files after the passage or speaker they belong to, for example intro-narration.mp3 or captain-warning.mp3. Match those names to the script list from Step 1. When a clip does not play later, a clear name tells you instantly whether the path is wrong or the file is missing.

Step 4: Embed the audio in your passages

How you trigger a clip depends on your story format.

In SugarCube, declare each track once (typically in your StoryInit passage) and then play it from any passage:

<<cacheaudio "warning" "audio/captain-warning.mp3">>

Then inside the passage where the line should sound:

<<audio "warning" play>>

In Harlowe, there is no audio macro, so you embed a standard HTML audio element directly in the passage. An element set to autoplay will sound when the player arrives at that passage:

<audio src="audio/captain-warning.mp3" autoplay></audio>

If you want a clickable "play line" control instead of autoplay, drop the autoplay attribute and add controls so the player sees a small audio bar. Either way, the file path is relative to the published HTML, which is why Step 3's folder discipline matters.

Step 5: Handle branching so audio follows the player

The thing that makes interactive fiction different from a linear audiobook is that the player chooses the path, and the audio has to follow. A few habits keep this sane:

• Tie each clip to the passage that owns it. If a line only makes sense after a specific choice, put its audio in that branch's passage, not the shared one before the fork.
• Stop overlapping tracks. In SugarCube, use <<audio "trackname" stop>> when leaving a scene so a long clip does not bleed into the next passage. In Harlowe, keep clips short enough that they finish before a typical player moves on.
• Do not gate progress on audio. Some players will have sound off. Make sure the text still carries the story so a muted playthrough is complete on its own.

If your project is really an audio-first experience rather than a game with sound sprinkled in, you may want the reverse workflow, where the branching story is built around the audio from the start. How to make an interactive audio story covers that path. This guide assumes Twine is your engine and the audio is imported into it.

Step 6: Test and publish

Publish your story to a folder from Twine (Build, then Publish to File, keeping the audio folder alongside the exported HTML) and open it in a browser. Walk each branch and confirm the right clip plays at the right passage. Browsers block autoplay with sound until the player interacts with the page, so test by clicking into the story first; a "click to begin" opening passage solves this cleanly and gives you a natural place to start audio. Once every branch checks out, ship the folder the same way you would any Twine web build.

If your game leans heavily on distinct speaking characters, the multi-voice approach scales well. Related builder workflows worth a look: adding voice acting to a visual novel for a Ren'Py-style flow, and the GameLit audiobook approach if your project is closer to prose than to a branching engine.

The short version

Write your line list, generate each clip in AudioProducer with a distinct voice per character, download the MP3s into a named audio folder, and embed them per passage using SugarCube's <<audio>> macros or a plain HTML audio element in Harlowe. Tie clips to the branch that owns them, keep a muted playthrough playable, and test every path before you publish. AudioProducer makes the voices; Twine remains your game.

Building a game with characters that speak? See how to voice NPCs in your indie game.