Storytel rethinks audiobook narration with Voice Switcher, built on ElevenLabs

Storytel is one of the world's largest audiobook streaming and publishing companies, with core markets in Sweden, Denmark, Finland, and Norway. We partnered with Storytel to build Voice Switcher, a feature that lets listeners choose between the original human narrator and an AI-narrated version of the same audiobook.

A long-standing listener problem

Storytel's user data showed that nine out of ten customers sometimes give up on an audiobook not because of the book itself, but because they do not connect with the narrator's voice. At the same time, audiobooks were almost never recorded with two narrators - the economics of traditional production did not support it.

Voice Switcher was built to close that gap.

Why Storytel chose ElevenLabs

Storytel had been working on AI voice for years before partnering with ElevenLabs. When Storytel saw an early ElevenLabs demo in 2023, the quality was a clear step up from anything they had evaluated before. That demo led to the start of our collaboration.

"We were blown away by the quality. We had been interested in AI voices for a long time but they weren’t as good as what we saw from ElevenLabs."

— Johan Ståhle, Chief Product and Technology Officer at Storytel

A custom model for Nordic languages

Our English voices were strong enough for Storytel to pilot Voice Switcher in summer 2023, but the Swedish voices were not yet at the bar required for a full audiobook. We worked with Storytel to develop an improved model for Nordic languages, with Storytel contributing high-quality proprietary audio data from its catalog as one of the world's largest audiobook publishers.

The improved Nordic model was ready in late 2023.

Launch and Nordic rollout

Voice Switcher launched in Sweden in early 2024, fronted by a professional voice clone of one of Sweden's most popular narrators acting as the public ambassador for the feature. At the time, very few high-quality, long-format AI audiobook productions existed, which made Storytel and ElevenLabs among the first to deliver AI narration at this length and quality.

Voice Switcher has since launched in Denmark and Finland, each with an ambassador voice in the local language. Storytel continues to add AI narrations alongside human originals across a growing portion of its catalog.

Scaling toward fully automated production

Storytel produces Voice Switcher narrations through the ElevenAPI, with internal pre- and post-processing on top. Pronunciation dictionaries, pre-generated proper nouns, and character-name checks help lift quality before final rendering.

Storytel's long-term goal is to make Voice Switcher available across its full catalog. Reaching that goal depends on continuing to reduce the manual editing currently required, and we are working with Storytel to move toward fully automated, API-driven production at scale.