Introduction
In Canada, public-facing websites are typically offered in both official languages: English and French. When validating websites for accessibility, we have a responsibility to test in both languages and ensure nothing was overlooked. However, auditing with the Non-Visual Desktop Access (NVDA) screen reader in a multilingual environment requires a bit of an initial configuration and a basic understanding of how voice synthesizers work.
For the sake of this article, I'm going to assume you have an English installation of NVDA and are trying to assess French a document, but the same guidelines apply for any other languages you may need to support.
Voice synthesizers
Also referred to as speech synthesizers or text-to-speech (TTS) engines, voice synthesizers are the component of screen readers that convert text into spoken audio.
In a nutshell, screen readers work by interpreting on-screen content and providing details of elements like images, headings, and the document's structure. This interpreted information is then, using the speech synthesizer, relayed to the user as spoken audio.
NVDA is compatible with many popular voice synthesizers and boasts support for commercial versions like Eloquence and Vocalizer, but these are not part of the standard installation and require a separate purchase.
Choosing a synthesizer
Synthesizers like eSpeak NG prioritize flexibility and broad language support while others, like Vocalizer and Microsoft OneCore Voices, prioritize natural-sounding speech.
Selecting a synthesizer is a personal preference that can vary based on your needs. The primary focus of this article will be on the Microsoft OneCore Voices as its typically the most comfortable synthesizer to use for new users.
In NVDA, selecting a speech synthesizer is done in the Speech preferences panel.
- NVDA menu
- Preferences
- Speech
Configuring OneCore Voices
Unlike other synthesizers, Microsoft OneCore Voices relies on the system's installed language packs to process text. In other words, unless you've previously installed them, you will not have French voices available by default.
To add text to speech packs for individual languages, navigate to the Windows Language and Region settings panel and manually install the desired languages and dialects.
- Settings
- Time and Language
- Language and Region
When installing language packs, you should also install the dialects you expect to encounter. For French, you should install both the default French pack for the voice and the French (Canada) pack for compatibility. This is because documents may be encoded with the generic French "fr" attribute or "fr-CA" for the Canadian French variant.
After restarting NVDA, new French voices such as Caroline and Claude can be found in NVDA's Speech settings panel, which confirms that the packs were installed correctly.
Automatic language switching
Automatic language switching, as its name suggests, will dynamically change the spoken language as long as the voice synthesizer supports it and the content is correctly marked up. The option should be enabled by default but it can be turned on or off in NVDA's Speech settings panel.
Application language
When NVDA provides an element's details, it uses the language its configured with and not the language of the contents it's reading out. For example, an English NVDA installation will announce a French heading as "Bienvenue sur notre site web Heading level 1".
By default, NVDA adopts Windows' language setting. However, if you prefer a more immersive testing experience, you can modify this in the General Settings section.
Working with profiles
The fastest way I've found to manually switch between languages for testing is by using profiles; one for French, one for English. Unfortunately, profiles do not capture the NVDA application language so that will need to be toggled as needed.
To add or manage profiles, first apply the desired language and speech settings, and save the profile. Repeat the process for the other languages. Profiles can then be toggled on and off in the Configuration Profiles menu which can also be opened with the shortcut NVDA key + Ctrl + P.
- NVDA menu
- Configuration profiles