Realistic Text-to-Speech (TTS) FAQs
Realistic Text-to-Speech — Frequently Asked Questions
What is realistic Text-to-Speech in BookFusion?
Realistic Text-to-Speech reads your eBooks, PDFs, and saved articles aloud in natural, human-sounding voices instead of the flat robotic voices built into your phone or computer. BookFusion generates the narration as you listen, so any book in your library can be listened to like an audiobook without converting or downloading an audio file first.
Can BookFusion turn my eBooks into audiobooks?
Yes. Open any EPUB, PDF, or article in your BookFusion library, tap Listen, choose a realistic voice, and press play. The narration is created on demand while you listen, so there is no conversion step, no waiting for a file to render, and no separate audiobook to store or transfer.
Which plans include realistic Text-to-Speech voices?
Offline realistic voices are available on every plan — Free, Casual, Advanced, and Power. Unlimited streaming of realistic voices is included with Advanced and Power plans across Web, iOS, and Android. There is no additional charge for either on any plan that includes them.
Is there a limit on how much I can listen to?
No. Streaming on Advanced and Power plans is unlimited — no tokens to buy, no character caps, no metered minutes, and no monthly listening allowance. Offline voices run on your own device, so there is no limit there either. You can listen to a full novel in one sitting without watching a counter.
Does BookFusion Text-to-Speech work offline?
Yes, on iOS and Android. Offline voices run entirely on your device and need no internet connection at all. On iOS, Supertonic voices are built into the app and support 31 languages offline. On Android, offline voices come through the free BookFusion Voice companion app, with 100+ voices across 38+ languages. Streaming voices require a connection and are available on Web, iOS, and Android.
What languages does BookFusion Text-to-Speech support?
Streaming supports 31 languages through Supertonic voices — Arabic, Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish, Ukrainian, and Vietnamese — alongside 9+ languages on our custom Kokoro voices, including English (US and UK), Spanish, French, Mandarin, Japanese, and Hindi. Android offline coverage extends to 38+ languages through BookFusion Voice.
Which voice models does BookFusion use?
Streaming voices run on custom Kokoro models with our own tuning, plus Supertonic voices. Offline voices use Supertonic on iOS and the BookFusion Voice catalog on Android. We built and operate the streaming service ourselves rather than reselling a third-party API, which is why unlimited listening does not raise your subscription price.
Does Text-to-Speech work with PDFs?
Yes. Both system voices and realistic voices work in PDFs on Android and iOS, alongside EPUBs and saved articles.
Can I follow along on screen while listening?
Yes. BookFusion highlights each sentence as it is spoken, so your eyes can track the text while your ears do the work. You can also skip forward or back one sentence at a time and adjust playback speed. Sentence highlighting is available with supported voices.
Is my book sent to BookFusion’s servers when I listen?
It depends on which voices you choose. Streaming voices send text to our Text-to-Speech service to generate audio. Offline voices process everything locally on your device and send nothing anywhere. If you would rather your content never leave your device, use the offline voices — they are available on every plan for exactly this reason.
Do I need to download a voice before I can listen?
Only for offline listening. Streaming voices work immediately with no download. Offline voices require a one-time download of the voice model, after which they generate speech on your device on demand — you never wait for a full audiobook to render.
How is this different from running my own Text-to-Speech setup?
Open-source projects such as Audiblez, epub_to_audiobook, and ebook2audiobook can produce excellent results, but they ask you to install dependencies, work from a command line, download models, sometimes rent GPU time, then generate and transfer the finished audio file yourself. BookFusion does the narration inside the reader you already use, generated as you listen, with your library, reading position, highlights, and notes staying in sync across Web, iOS, and Android.
Does realistic Text-to-Speech replace audiobooks?
No, and it is not meant to. A professionally narrated audiobook is a creative performance that synthetic voices do not match. Realistic Text-to-Speech gives a voice to everything that will never get an official audiobook edition — older titles, textbooks, research papers, technical documents, and the files you scanned or wrote yourself.
How do I turn on realistic voices in BookFusion?
Open a book, tap Listen, then select a voice. On Android, tap Select Voice, open the Advanced section, and preview the voices before confirming your choice. Full setup instructions for every platform are in the Text-to-Speech & Audio documentation.
Realistic Text-to-Speech reads your eBooks, PDFs, and saved articles aloud in natural, human-sounding voices instead of the flat robotic voices built into your phone or computer. BookFusion generates the narration as you listen, so any book in your library can be listened to like an audiobook without converting or downloading an audio file first.
Yes. Open any EPUB, PDF, or article in your BookFusion library, tap Listen, choose a realistic voice, and press play. The narration is created on demand while you listen, so there is no conversion step, no waiting for a file to render, and no separate audiobook to store or transfer.
Offline realistic voices are available on every plan — Free, Casual, Advanced, and Power. Unlimited streaming of realistic voices is included with Advanced and Power plans across Web, iOS, and Android. There is no additional charge for either on any plan that includes them.
No. Streaming on Advanced and Power plans is unlimited — no tokens to buy, no character caps, no metered minutes, and no monthly listening allowance. Offline voices run on your own device, so there is no limit there either. You can listen to a full novel in one sitting without watching a counter.
Yes, on iOS and Android. Offline voices run entirely on your device and need no internet connection at all. On iOS, Supertonic voices are built into the app and support 31 languages offline. On Android, offline voices come through the free BookFusion Voice companion app, with 100+ voices across 38+ languages. Streaming voices require a connection and are available on Web, iOS, and Android.
Streaming supports 31 languages through Supertonic voices — Arabic, Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish, Ukrainian, and Vietnamese — alongside 9+ languages on our custom Kokoro voices, including English (US and UK), Spanish, French, Mandarin, Japanese, and Hindi. Android offline coverage extends to 38+ languages through BookFusion Voice.
Streaming voices run on custom Kokoro models with our own tuning, plus Supertonic voices. Offline voices use Supertonic on iOS and the BookFusion Voice catalog on Android. We built and operate the streaming service ourselves rather than reselling a third-party API, which is why unlimited listening does not raise your subscription price.
Yes. Both system voices and realistic voices work in PDFs on Android and iOS, alongside EPUBs and saved articles.
Yes. BookFusion highlights each sentence as it is spoken, so your eyes can track the text while your ears do the work. You can also skip forward or back one sentence at a time and adjust playback speed. Sentence highlighting is available with supported voices.
It depends on which voices you choose. Streaming voices send text to our Text-to-Speech service to generate audio. Offline voices process everything locally on your device and send nothing anywhere. If you would rather your content never leave your device, use the offline voices — they are available on every plan for exactly this reason.
Only for offline listening. Streaming voices work immediately with no download. Offline voices require a one-time download of the voice model, after which they generate speech on your device on demand — you never wait for a full audiobook to render.
Open-source projects such as Audiblez, epub_to_audiobook, and ebook2audiobook can produce excellent results, but they ask you to install dependencies, work from a command line, download models, sometimes rent GPU time, then generate and transfer the finished audio file yourself. BookFusion does the narration inside the reader you already use, generated as you listen, with your library, reading position, highlights, and notes staying in sync across Web, iOS, and Android.
No, and it is not meant to. A professionally narrated audiobook is a creative performance that synthetic voices do not match. Realistic Text-to-Speech gives a voice to everything that will never get an official audiobook edition — older titles, textbooks, research papers, technical documents, and the files you scanned or wrote yourself.
Open a book, tap Listen, then select a voice. On Android, tap Select Voice, open the Advanced section, and preview the voices before confirming your choice. Full setup instructions for every platform are in the Text-to-Speech & Audio documentation.
