FolioDuet Read with every sense PDF audiobook-style reader

Synchronized PDF read-along

Read and listen to your PDF at the same time

Hear the words. See your place. FolioDuet reads your PDF aloud while highlighting the current word, so your eyes and ears stay on the same line.

Try the synchronized demo Choose my PDF
The FolioDuet reader highlighting a spoken word on the open page

Your original PDF stays on this device. Extracted text can sync after sign-in, and neural speech sends the narrated passage to the selected TTS provider. Read the privacy details

The FolioDuet reading surface with the spoken word impossible highlighted on page two
The visible highlight follows narration inside the same reading surface—no separate audio window.

The read-along, in one frame

Visual transcript: The library and open book appear together. The current page is centered like a sheet of paper; “impossible” is highlighted in amber during narration, with page number and overall reading progress still visible.

One synchronized surface

What simultaneous reading means here

The voice, visible text, and your saved place move as parts of the same reader.

Current-word highlight

Speech timing updates the active word so you can follow the line instead of hunting for your place.

Reading controls

Pause, resume, choose a starting word, and cycle between playback speeds from 0.8× to 2×.

Progress through pages

Narration continues through readable blocks, updates the page, and remembers where you stopped.

Who it may suit

For people who prefer more than one way into a text

Reading and listening together is sometimes called bimodal reading. FolioDuet provides the mechanics without making medical or comprehension guarantees.

Less window juggling

Text and sound share one reading surface

A standalone PDF window can show the page, and a separate audio player can carry the sound. FolioDuet connects those two states: the word you hear is also the place you see.

You can tap a word in the reading layer to begin there, then keep the playback controls, page movement, and progress together.

Start in the browser

Demo first, your document next

  1. Open the synchronized sample without signing in.
  2. Import a text-based PDF with selectable text.
  3. Choose a word or press play and follow the highlight.
Open the demo

Before you begin

What the reader processes—and what it does not

  • A PDF must contain a usable text layer; built-in OCR for image-only scans is not promised.
  • Complex columns, headers, or unusual encoding can affect extracted reading order.
  • Neural narration is streamed, needs a connection, and does not create an MP3 or M4B download.
  • Word timing and voice availability can vary with the speech provider or browser fallback.

Your files are not all treated the same: the original PDF remains on the import device. A signed-in library can sync extracted text and progress. Neural TTS processes only the text selected for speech through the configured provider. Consent-gated analytics can be declined without disabling the reader.

Frequently asked questions

Reading and listening in sync

Does FolioDuet highlight every word as it reads?

The active-word highlight updates from timing supplied by the speech engine. Neural providers with alignment data offer the intended synchronized experience; timing precision can vary when playback falls back to a browser system voice.

Can I click a word or passage to start there?

Yes. Words in the FolioDuet reading layer are selectable playback starting points.

Will it keep turning pages?

Playback advances through readable text blocks and updates the current reader page. A page without usable extracted text may have nothing to narrate.

Can I change the voice and speed?

Yes. The reader includes speech-provider and voice settings, plus 0.8×, 1×, 1.2×, 1.5×, and 2× playback. Available voices depend on the provider or browser.

Does it work on phone and desktop?

FolioDuet has responsive phone and desktop layouts. Provider and browser voice support can differ between devices, so the exact set of voices is not universal.

Does it support image-only or scanned PDFs?

Not by itself. The PDF needs a usable text layer; FolioDuet does not currently promise built-in OCR for image-only scans.

Another way to describe it

The same continuous reader can help you listen to a PDF like an audiobook, while keeping the current page available whenever you look back at the screen.

FolioDuet is open source under the MIT License. The source and issue tracker are available on GitHub.

Start with one page

Put the voice and the words in the same place

Try the synchronized demo Choose my PDF