Text to Speech And Game Accessibility

Following is a guest post written by Conor Bradley, Founder and Director of Soft Leaf Studios.

I have been kindly invited to write a post on text to speech, and how we can use it to help make video games more accessible. For those of you who are not familiar, text to speech (TTS) is a bit of software that takes the text given to it and reads it back in a synthesized voice.

At Soft Leaf Studios we take accessibility very seriously. With our current game, Stories of Blossom, we have been designing and testing from the start of production to ensure we remove as many barriers as we can for those with disabilities. Text to speech is one of the tools we are using to achieve that.

How does text to speech benefit gamers around the world?

Many gamers face the same challenges you’re used to hearing about in other contexts:

• They may have trouble seeing visual content on screen due to a visual impairment.
• They may have trouble reading text due to low literacy skills, or the text is not in their native language.
• They may have trouble communicating with other online players through voice chats.

Text to speech helps gamers overcome all these challenges. Without it, we are excluding some players from enjoying our games. The only way they could experience them would be to have an assistant narrate and navigate the game along with them. This is not an option for most people, and is far from ideal.

Game Areas Where Text to Speech is Helpful

In most games, key information that is usually expressed only by text or through visual means includes:

• Menus and the heads-up display (HUD)
• Text logs, non-voiced dialogue, and chat windows
• On-screen prompts such as objectives, tutorial instructions, and button prompts
• Traversing a game’s world and interacting with its objects
• Communication with other players
• Gameplay events and cutscenes that lose context without their visuals

If none of this information is narrated, players may not be able to start your game, let alone enjoy playing it.

This is where text to speech can help. Most game engines only output pixels to screen, offering nothing for screen readers to work with. This means it is up to us as developers to pass the text forward. Interactable elements and any text-based content are a great place to start. We can add text to speech calls to events, such as focusing on a UI element, or the enabling of a screen prompt or passage of text.

Almost any game can benefit from this, but why stop there? We can give any kind of interaction a call to the text-to-speech system to give the player further context. Using our game, Stories of Blossom, as an example, when a player focuses on an interactable object they also receive context about what the object is, and the button they need to press to interact with it.

These kinds of in-game objects usually have some form of name associated with them that we can use. It gets a little tricky scheduling what to read and when, but I’ll share my approach for Soft Leaf Studios’ games as one example for handling text to speech:

Before reading a line I add it to a queue. I order these lines by determining what information the player needs to hear first, and what they can wait to hear. This gets interrupted when the player triggers another call before forming a new queue.

It can be tiresome to hear certain information over and over, so I like to cull lines when I can. I check, for example, if players have heard a common button prompt recently, or if the game state has changed. As soon as players become familiar with your game they may not need as much of this information. This is where a simple toggle on or off for these kinds of lines can improve the experience. You will have to write custom strings of text for these in most cases, but players really do appreciate it.

Areas That Are Challenging, But Not Impossible

Games that rely heavily on UI information will be more of a challenge to navigate and prioritize. This is why seeking the help of the disability community and others to test your solutions is a must. Their feedback will be critical in shaping the accessibility of your game.

Depending on your game’s complexity, narrating the traversal of your game’s world can become a challenge. I recommend looking into this early in development to identify what is going to work and what will not. Again, get testers in at this point to help out.

One area rarely considered are game events that lose context without visuals. Blind players are often left in the dark as to what is happening during a scene that has little to no audio. Audio descriptions can help provide this missing context. There is a lot of information that can be expressed that we sometimes take for granted; these small details make our games unique. These descriptions may include the physical appearance of characters, facial expressions, the setting, and the art style, to name a few. When you don’t have the budget for a voiced audio description, text to speech is the logical and most cost-effective place to look.

ReadSpeaker’s Practical Game Engine Plugin

From the beginning of our game’s prototype we knew we needed text to speech to help players navigate our game. Using ReadSpeaker’s new text-to-speech plugin, we were able to make this happen—I don’t know where we would be without it. It saves us having to generate audio files and then add them to our project. We can simply do this in real time when the game needs them. This saved a lot of development time when auditioning the lines to be read; I just had to change a string of text if I was not happy with it.

We use text to speech for any event that is not already voiced by a voice actor. The blend of the two works quite nicely. The plugin gives players the ability to customize the voice of their speaker, the reading speed, and the pitch. One thing we discovered through testing was that some of our players found our max speed not fast enough, so we now have increased that by a large margin.

If you have the ability to add text to speech to your game, I would recommend it. There are many things that go into making a game accessible, and text to speech is one of them. I also recommend checking out the various game accessibility guidelines available to learn more on this topic.

Soft Leaf Studios’ project is funded by Future Screens NI and Northern Ireland Screen.