Windows 10/11: Settings → Time & language → Language & region → Add a language → Next → Install language pack
Windows 10/11: Settings → Time & language → Typing → Advanced keyboard settings → Use the desktop language bar (if needed)
Windows 10/11: Use the language switch shortcut: Windows key + Space
Windows 10/11: Remove a language: Settings → Time & language → Language & region → select language → Remove
macOS (Ventura/Sonoma): System Settings → Keyboard → Text Input → Edit → Add Input Source → select language/keyboard
macOS: Use the shortcut: Control + Space (if enabled) or select input source from the menu bar
macOS: Remove an input source: System Settings → Keyboard → Text Input → Edit → remove
iPhone/iPad (iOS/iPadOS): Settings → General → Keyboard → Keyboards → Add New Keyboard → select language
iPhone/iPad: Settings → General → Keyboard → Keyboards → select desired keyboard
Android: Settings → System → Languages & input → On-screen keyboard → Manage keyboards → Add keyboard → select language
Android: Settings → System → Languages & input → Physical keyboard (if applicable) → select language/layout
ChromeOS: Settings → Keyboard → Manage keyboards → Add input method → select language
Linux (GNOME): Settings → Region & Language → Input Sources → + → select language/keyboard
Linux (KDE Plasma): System Settings → Input Devices → Keyboard → Layout → Add → select language/keyboard