Frequently Asked Questions

SleepLearn is an iOS language learning app for reinforced vocabulary practice. You can use active learn sessions for focused study, then switch to sleep sessions for quieter bedtime review with target-language words, optional English translations, audio, repetition, and gentle pacing.

No. SleepLearn is best used as a relaxed vocabulary review tool alongside normal study, reading, listening, speaking practice, and review. Sleep can help consolidate vocabulary you studied while awake, and replaying selected word cues during sleep may improve recall, but SleepLearn does not guarantee fluency, retention, or any specific learning result.

SleepLearn is inspired by research on sleep, memory consolidation, and targeted memory reactivation. Several studies suggest that sleep can support memory for material studied while awake, and that carefully replayed word cues during sleep may improve later recall. These findings are limited and do not mean audio can replace active study.

• Schreiner & Rasch, 2015: verbal cues during sleep improved later recall of vocabulary pairs that participants had studied before sleep.
• Goldi & Rasch, 2019: at-home cueing effects depended on sleep quality and whether audio disturbed the sleeper.
• Zust et al., 2019: lab results suggested some implicit word-association learning can occur during specific slow-wave sleep timing, but this was not a fluency or active-study replacement.

No account is required for the core app experience. Your language choices, session settings, progress, known words, favorites, and history are stored on your device.

Learn sessions are for active vocabulary practice when you are awake and focused. Sleep sessions use a dimmer, quieter flow with bedtime-friendly pacing, sleep timers, optional ambient sound, and next-morning recall support. Both modes reinforce vocabulary through repetition, exposure history, favorites, known words, and progress tracking.

Pick a language, level, and session size, then start a sleep session. The app shows each word and translation in a dim interface, plays the audio sequence, waits for the pause interval you selected, and moves to the next word.

Yes. In settings, you can choose repetitions per word, playback speed, whether English translations play, the pause between words, and whether to focus on favorited words only.

The sleep timer can stop playback after 15, 30, or 45 minutes, after 1 or 2 hours, or at the end of the current session. During the final minutes of a timed session, SleepLearn gradually fades the volume down.

Yes. SleepLearn includes ambient options such as ocean waves, soft rain, brown noise, pink noise, gentle stream, and distant fireplace. Ambient sound volume follows the sleep timer fade so the whole session winds down smoothly.

The Sleep Frequency Layer is an optional, off-by-default experimental audio layer that generates very low-volume stereo tones underneath the vocabulary voice and any ambient sound. It works best with stereo headphones, has its own capped volume control, and follows the sleep timer fade.

Evidence for binaural beats and sleep is mixed. SleepLearn does not claim that this feature improves sleep, induces deep sleep, treats insomnia, or affects any health condition. Keep the volume low, do not use it while driving or anywhere alertness is required, and stop if the tones feel uncomfortable.

SleepLearn supports Spanish, French, German, Italian, Portuguese, Russian, Japanese, and Korean.

European languages use CEFR-style levels from A1 through B2+. Japanese uses JLPT levels N5 through N1. Korean uses TOPIK-style levels, including TOPIK I and TOPIK II coverage.

The app currently offers session sizes such as 50, 75, and 100 words, depending on the screen and content available for the selected language and level.

SleepLearn prioritizes vocabulary based on your selected language and level, then uses your local exposure history to help surface words you have seen less often. Words marked as known can be filtered out of future learning sessions.

The first time you start some language and level combinations, SleepLearn may need to prepare audio resources. Keep the app open while the progress screen is visible. After the required assets are ready, playback can continue normally.

Vocabulary and prepared audio resources are available on device. Some audio assets may need to be downloaded or prepared before offline use, especially the first time you use a language, level, or translation audio set.

SleepLearn is designed for in-app audio playback during active sleep sessions. If you leave the app or switch away, playback may pause or stop.

Where bundled audio choices are available, SleepLearn can use automatic, male, or female audio preferences for supported language audio.

SleepLearn tracks session history, word exposure counts, daily progress, streaks, known words, favorited words, and related learning preferences on your device.

Favorites let you collect words you want to review again. Known words let you mark vocabulary you already recognize so SleepLearn can avoid showing it as often in regular learning sessions.

Yes. You can enable a bedtime reminder and choose a reminder time. Notifications can be changed in SleepLearn or disabled in iOS settings.

SleepLearn does not require an account for core use. The app stores learning progress and settings locally on your device. If you contact us by email, we receive the information you choose to send.

You can remove app data by deleting the app from your device. You can also manage known words, favorites, reminders, and settings inside the app where those controls are available.

The full policy is available at https://niryph.com/sleeplearn/privacy.html.

• Make sure your device volume is up and Silent Mode or Focus settings are not blocking audio.
• Keep the app open if it is still preparing audio assets.
• Check whether the session is paused or the sleep timer has faded volume near the end.
• Try starting a new session after closing and reopening the app.

Repetition is intentional. SleepLearn can repeat a word multiple times in one audio sequence, and it may resurface words over time based on exposure history and your settings.

The sleep timer may have ended, the selected session may have finished, iOS may have interrupted audio, or the app may have been closed by the system.

Email us at contact@niryph.com. Please include your device model, iOS version, SleepLearn app version if available, selected language and level, and a short description of the issue.