FAQ

DexSpeak plays YouTube videos using YouTube’s official iFrame Player API.

YouTube loads and plays its videos directly. DexSpeak does not control YouTube’s playback service. If YouTube rejects the network request or requires sign-in verification, playback in DexSpeak may also fail.

Your current network environment may affect YouTube’s embedded player.

If playback fails, shows an error, or asks you to sign in to YouTube, try another available network and retry.

If the issue is caused by your current network environment, using another available network may restore playback.

The two apps use different playback methods.

The YouTube app is YouTube’s own client and is usually signed in to a Google account, so it can use YouTube’s own authentication and playback mechanisms.

DexSpeak uses YouTube’s official iFrame Player API, the embedded YouTube player. For third-party embedded playback, YouTube may perform additional checks based on the current IP address, network environment, and request details.

As a result, this can happen:

The YouTube app plays a video normally, while the YouTube player in DexSpeak cannot play it.

DexSpeak uses YouTube’s embedded player, so playback can differ from the YouTube app. DexSpeak cannot bypass YouTube’s sign-in or access checks. Try the network steps above if you encounter a playback problem.

If this happens, refer to the network troubleshooting guidance above.

Text-to-speech (TTS) reads book text aloud. DexSpeak supports system voices and downloaded local voices. Downloaded voices run on your device and may need substantial memory and processing power.

Some mobile browsers may not have enough memory to load or run a downloaded voice. The Android app uses an embedded browser and may face the same limits. System voice availability and playback also depend on your device and browser.

If a downloaded voice does not work, try a system voice in the voice settings. If playback is still unstable, try a desktop browser.

If your current App Store region is mainland China, opening Library in My Books in DexSpeak shows a notice that the feature is unavailable in your App Store region due to regional compliance requirements.

Due to compliance requirements in mainland China, Library is currently unavailable for the mainland China App Store region.

You can still use Library in the DexSpeak web app, or download DexSpeak from the App Store in another supported region. Feature availability depends on your current App Store region.

PDF book uploads are not currently supported. Please use EPUB format.

EPUB is better suited to reading on different screen sizes: text reflows to fit the screen, and you can adjust the font, font size, and line spacing for comfortable reading.

PDF is designed primarily to preserve a fixed page layout. On a phone, this often requires repeated zooming and dragging, and text layout cannot be adjusted as freely as with EPUB. Some scanned PDFs contain images rather than selectable text, making text selection and word lookup difficult. DexSpeak therefore currently uses EPUB for e-books.