Conjuga

A Spanish-learning iOS app that combines verb conjugation practice, a full textbook reader, an AI conversation partner, offline dictionary lookups, grammar exercises, and more. Runs entirely on-device where possible (Foundation Models, Speech framework, Vision OCR).

Features

Verb practice

• Six conjugation modes — flashcards, typing, multiple choice, handwriting (Apple Pencil / finger), sentence builder, and full-table (conjugate all persons at once)
• Focus modes — weak verbs (SM-2 spaced repetition), irregularity drills (spelling / stem / unique), common tenses
• 1,750 verbs across 5 levels (Basic → Expert) with 209 K pre-conjugated forms and 23 K irregular-span annotations
• 20 tenses — every indicative, subjunctive, conditional, and imperative tense, each with character-level irregular highlighting
• Verb list filters — search by level, by irregularity (Any / Spelling Change / Stem Change / Unique Irregular), or by reflexive only (curated 100-verb list); filters compose
• Practice pool filters (Settings) — multi-select per level, per tense, per irregular-type, plus a "reflexive verbs only" toggle. Practice pool = intersection of all four.
• Verb detail pages — conjugation table, six AI-generated example sentences (one per core tense), and reflexive infinitive + preposition hint for curated reflexive verbs
• Text-to-speech on any form

Content & study

• Textbook reader — 30 chapters of Complete Spanish Step-by-Step with 251 interactive exercises (keyboard + Apple Pencil), 931 OCR'd vocab tables rendered as Spanish→English grids (~3 100 paired cards extracted via bounding-box OCR)
• Course decks — weekly vocab decks with example sentences, week tests, and cumulative checkpoint exams
• Stem-change toggle on Week 4 flashcard decks (E-IE, E-I, O-UE, U-UE) showing inline present-tense conjugations
• Grammar guide — 20 tense guides with usage rules and examples + 36 grammar topic notes (ser/estar, por/para, preterite/imperfect, reflexives, subjunctive triggers, etc.), each with 100+ practice exercises
• Grammar exercises — interactive quizzes for 5 core topics (ser/estar, por/para, preterite/imperfect, subjunctive, personal a)
• Curated YouTube videos — 54 hand-picked videos attached to guide and grammar items (preference for The Language Tutor's numbered lessons + BaseLang). Each item offers three actions: Stream (opens YouTube app / Safari), Download (YouTubeKit extraction + AVFoundation mux for modern adaptive-stream videos), Play (full-screen AVPlayer from local MP4). Settings → Downloaded Videos lists all downloads with total size, per-item delete, and a 500 MB warning.

AI & speech

• Conversational practice — on-device AI chat partner (Apple Foundation Models) with 10 scenario types; chat bubbles have tappable words that open dictionary / on-demand AI lookup
• AI short stories — generated stories with tappable words and comprehension quizzes
• Listening practice — listen-and-type + pronunciation scoring via the Speech framework
• Pronunciation check — word-by-word match scoring

Vocabulary & tools

• Offline dictionary — reverse index of 175 K verb forms + 200 common words, cached to disk for instant lookups
• Vocab SRS review — spaced repetition over course vocabulary with Again / Hard / Good / Easy rating
• Cloze practice — fill-in-the-blank sentences with distractor generation
• Lyrics practice — search, translate, and read Spanish song lyrics; long-press any word for an instant definition + tense/person readout (for verbs)

Tracking & sync

• Progress — streaks, daily goals, accuracy stats, achievement badges, study-time tracking per day
• CloudKit sync — review progress, test results, saved stories, conversations, and textbook attempts sync across devices
• Widgets — combined dashboard + word-of-the-day, refreshed daily and on backgrounding

Architecture

• SwiftUI + SwiftData with a dual-store configuration:
  • Local store (App Group group.com.conjuga.app) — reference data + per-device artifacts: verbs, forms, irregular spans, tense guides, course decks, vocab cards, textbook chapters, and downloaded videos. Seeded from bundled JSON on first launch. Self-healing re-seeds trigger on version bumps or if rows are missing on disk.
  • Cloud store (CloudKit iCloud.com.conjuga.app, private database) — user data: review cards, course reviews, user progress, test results, daily logs, saved songs, stories, conversations, textbook exercise attempts.
• SharedModels Swift Package shared between the app and widget extension. Widget schema must include every local-store entity or SwiftData destructively migrates the shared store.
• Foundation Models for on-device AI generation (@Generable structs for typed output) — conversation partner, short stories, verb-detail example sentences.
• Vision framework for OCR of textbook pages and vocabulary images.
• Speech framework for recognition and pronunciation scoring.
• YouTubeKit (SPM) for video stream URL extraction, paired with AVFoundation (AVMutableComposition + AVAssetExportSession passthrough) to mux separate DASH video + audio tracks into a single MP4 when progressive streams aren't available.
• Textbook extraction pipeline (Conjuga/Scripts/textbook/) — XHTML and answer-key parsers, macOS Vision image OCR + PDF page OCR, bounding-box vocab pair extractor, NSSpellChecker-based validator, and language-aware auto-fixer.
• Video curation tooling (Conjuga/Scripts/generate_videos_markdown.py) — regenerates Conjuga/youtube_videos.md with per-video channel, upload date, duration, view count, and like count (pulled via yt-dlp).

Requirements

• iOS 26+ (Foundation Models, Liquid Glass, modern Swift concurrency)
• Xcode 26+
• Apple Intelligence-capable device for AI features (conversation partner, AI stories, verb-detail examples); other features degrade gracefully

Building

Open Conjuga/Conjuga.xcodeproj in Xcode and run on a simulator or device. Reference data seeds automatically on first launch. To regenerate textbook content, run Conjuga/Scripts/textbook/run_pipeline.sh locally — the generated textbook_data.json / textbook_vocab.json are committed so fresh clones build without the pipeline.