Patter
Language learning that feels like texting a friend. Chat with AI personas who stay in character, correct your grammar in real time, and adapt to your level — all without an account or a server.
How it works
Patter is serverless and BYOK (Bring Your Own Key). There is no developer backend — your conversations live on your device, and all AI calls go directly from your phone to your chosen LLM provider using your own API key stored in the iOS Keychain. Start a chat with an AI persona who speaks only your target language, make mistakes, get corrected, and learn naturally.
Highlights
- iMessage aesthetics — custom SwiftUI chat bubbles with asymmetric tail corners; blue for you, gray for AI. Feels like texting a friend.
- Real-time grammar corrections — collapsible correction banners appear below your messages when you make a significant error, so you learn as you go.
- Tap-to-translate — tap any message to flip it to your native language; long-press individual words for gloss-level popovers.
- AI personas — each contact has a name, emoji, backstory, tone, and interests; generated once at creation time and they stay in character.
- CEFR level selector — switch difficulty mid-conversation (A1–C1); the system instruction rebuilds locally with no extra API call.
- Proactive pings — local notifications simulate a contact starting a conversation after you've been away, keeping your streak alive.
- Daily goal & streak — tracks consecutive days of practice; survives app reinstall.
- Zero server — no account, no cloud storage, no data leaves your device except to your LLM provider.
Supported languages
Patter supports 10 languages with dialect-specific rules:
- English (US, GB)
- Spanish (Castilian, Latin American)
- Portuguese (European, Brazilian)
- French (France, Canadian)
- German
- Italian
- Japanese
- Mandarin
- Korean
- Russian
Get the app
Patter is available on the App Store for iPhone (iOS 17 or later). You'll need your own API key from a supported provider (Google AI Studio, OpenAI, Anthropic).