localization-ios

# Localization iOS — Expert Decisions

Expert decision frameworks for localization choices. Claude knows NSLocalizedString and .strings files — this skill provides judgment calls for architecture decisions and cross-language complexity.

---

## Decision Trees

### Runtime Language Switching

```
Do users need in-app language control?
├─ NO (respect system language)
│  └─ Standard localization
│     NSLocalizedString, let iOS handle it
│     Simplest and recommended
│
├─ YES (business requirement)
│  └─ Does app restart work?
│     ├─ YES → UserDefaults + AppleLanguages
│     │  Simpler, more reliable
│     └─ NO → Full runtime switching
│        Complex: Bundle swizzling or custom lookup
│
└─ Single language override only (e.g., always English)
   └─ Don't localize
      Bundle.main with no .lproj
```

**The trap**: Implementing runtime language switching when system language suffices. It adds complexity and can break third-party SDKs that read system locale.

### String Key Architecture

```
How to structure your keys?
├─ Small app (< 100 strings)
│  └─ Flat keys with prefixes
│     "login_title", "login_email_placeholder"
│
├─ Medium app
│  └─ Hierarchical dot notation
│     "auth.login.title", "auth.login.email"
│
├─ Large app with teams
│  └─ Feature-based files
│     Auth.strings, Profile.strings, etc.
│     Each team owns their strings file
│
└─ Design system / component library
   └─ Component-scoped keys
      "button.primary.title", "input.error.required"
```

### Pluralization Complexity

```
Which languages do you support?
├─ Western languages only (en, es, fr, de)
│  └─ Simple plural rules
│     one, other (maybe zero)
│
├─ Slavic languages (ru, pl, uk)
│  └─ Complex plural rules
│     one, few, many, other
│     e.g., Russian: 1 файл, 2 файла, 5 файлов
│
├─ Arabic
│  └─ Six plural forms!
│     zero, one, two, few, many, other
│     MUST use stringsdict
│
└─ East Asian (zh, ja, ko)
   └─ No grammatical plural
      But may need counters/classifiers
```