EN-UA Switcher

Automatic keyboard layout switcher and EN/UA text conversion utility for Windows.

EN-UA Switcher is a Windows tray app for switching mistyped English/Ukrainian text.

If you type руддщ instead of hello, EN-UA Switcher can fix it automatically after a delimiter or manually through global hotkeys.

What It Does

• Auto-corrects the last typed word on Space, Enter, or Tab
• Fixes the last word or selected text with global hotkeys
• Works with native Win32 editors, many browser inputs, and a range of Electron apps
• Keeps a live diagnostics log for troubleshooting
• Supports process exclusions and word exclusions
• Lets you undo the last auto-correction with Backspace

Modes

Auto Mode

Auto Mode watches the current word buffer and decides whether the word should be layout-switched.

• It evaluates both EN and UA interpretations of the typed token
• It uses a local scoring model with layout mapping, short-text heuristics, character patterns, and dictionary boosts
• It does not rely on a giant hardcoded word list alone
• It only runs on delimiter keys that you enable in settings

Example:

• typed: руддщ
• auto-corrected to: hello

Safe Hotkeys

Safe hotkeys do not "think". They always do a direct layout toggle.

Hotkey	Action
Ctrl+Shift+K	Toggle the last word before the caret
Ctrl+Shift+L	Toggle the selected text

This path is intentionally dumb and deterministic:

• no language detection
• no heuristics
• no confidence threshold

Tray Menu

EN-UA Switcher runs in the system tray.

From the tray menu you can:

• open the settings window
• toggle Auto Mode
• open diagnostics
• exit the app

Double-clicking the tray icon opens settings.

Settings

The settings window has 4 tabs.

General

• Enable Auto Mode: turns automatic correction on or off
• Correct on Space: tries auto-correction when Space is pressed
• Correct on Enter: tries auto-correction when Enter is pressed
• Correct on Tab: tries auto-correction when Tab is pressed
• Cancel on Backspace: clears the current word buffer so pending auto-correction will not fire
• Cancel on Left Arrow: same idea when you move the caret left
• Undo correction on Backspace: immediately rolls back the last auto-correction
• Start minimized to system tray: app starts hidden
• Enable diagnostics logging: enables the diagnostics window and file logging

Hotkeys

• Shows whether global hotkeys are currently registered
• Shows the current hotkey bindings
• Current defaults are:
  • Ctrl+Shift+K for the last word
  • Ctrl+Shift+L for selected text

Exclusions

There are two exclusion lists.

• Excluded processes: disables all correction logic inside selected apps
  • add from the running process list
  • add manually by process name without .exe
  • remove selected items from the visible list
• Excluded words: disables Auto Mode for specific words
  • add the word in either layout
  • the opposite layout form is excluded too
  • safe hotkeys still work because they are manual

Example:

• add привіт
• ghbdsn will also be skipped by Auto Mode

About

Contains a short summary, supported targets, hotkey reminder, and contact info.

Diagnostics

Diagnostics help explain why a correction happened or why it was skipped.

The diagnostics window shows:

• process name
• adapter used
• operation type
• original text
• converted text
• result
• reason

When file logging is enabled, logs are written to:

• %APPDATA%\Switcher\switcher-yyyy-MM-dd.log

Settings are stored in:

• %APPDATA%\Switcher\settings.json

Startup And Admin Notes

• Run at Windows startup uses the current-user HKCU\Software\Microsoft\Windows\CurrentVersion\Run key, so normal registration does not require admin rights
• The app now refreshes that startup entry on launch, which helps upgrades keep pointing at the current executable instead of an older release folder
• Normal startup is asInvoker and should not trigger a UAC prompt
• If you need to correct text inside an already elevated target app, Windows may require running EN-UA Switcher elevated too, because low-integrity processes cannot inject into higher-integrity windows

Supported Targets

Target	Status
Notepad, WordPad, classic EDIT / RichEdit controls	Good support in Auto Mode and hotkeys
Browser text inputs and textareas	Usually good, with UIA and clipboard fallback paths
Electron apps such as Telegram, Element, Codex-like editors	Mixed runtime quality depending on the editor control
contenteditable, Monaco, CodeMirror and similar custom web editors	Weakest path, especially in Auto Mode

Known Limitations

• KNOWN ISSUE: CHROME URL BAR AND YOUTUBE COMMENTS DO NOT WORK RELIABLY IN AUTO MODE YET. WE ARE WORKING ON THIS FIX.
• Regular Chrome page inputs that expose writable UI Automation still work; the current problem is specifically the Chrome URL/address bar and YouTube comment editor.
• Auto Mode still works through injected input and replacement paths, so in some editors you may briefly see the word tail move or flicker
• Browser and Electron behavior depends on what the target exposes through UI Automation, selection APIs, and clipboard behavior
• Custom editors are much less predictable than native text boxes
• One-letter words are intentionally handled conservatively in Auto Mode to avoid breaking normal English typing

Download

Portable release artifacts are published on the GitHub releases page:

• Releases

Release notes:

• bin\EN-UA-Switcher.exe is only the normal build output for local development
• EN-UA-Switcher.exe is the full self-contained Windows build and does not require a separate .NET install
• EN-UA-Switcher-runtime-dependent.exe is the smaller runtime-dependent build and requires the .NET 8 Desktop Runtime

Build From Source

Requirements:

• Windows 10 or 11
• .NET 8 SDK

Build:

dotnet build .\src\Switcher.App\Switcher.App.csproj -v minimal

Create a portable release package:

.\scripts\publish-release.ps1

Run from source:

dotnet run --project .\src\Switcher.App\Switcher.App.csproj

Run tests:

dotnet test .\tests\Switcher.Core.Tests\Switcher.Core.Tests.csproj -v minimal
dotnet test .\tests\Switcher.Engine.Tests\Switcher.Engine.Tests.csproj -v minimal

Run the proactive bulk audit:

.\scripts\bulk-auto-eval.ps1 -FetchLargeWordLists -EnLimit 50000 -UaLimit 50000 -ContextSample 1500

This fetches 50k English and Ukrainian corpora into artifacts\bulk-audit and runs the tools\BulkEval scenario audit over word, sentence, chat, short-phrase, brand, and mixed tech contexts.

Where The EXE Is

This repo is configured to place the app build output into the repository-level bin folder.

After a normal build, the main executable is typically here:

• bin\EN-UA-Switcher.exe

Other build outputs such as .dll, .pdb, and runtime config files are placed in the same folder.

This file is not the packaged end-user release by itself.

To create the actual release artifact, run the publish script above. It creates:

• artifacts\release\EN-UA-Switcher.exe
• artifacts\release\EN-UA-Switcher-runtime-dependent.exe
• artifacts\release\SHA256SUMS.txt
• artifacts\release\release-manifest.txt

The GitHub Actions release workflow uses the same script when you push a v* tag.

Project Structure

src/
  Switcher.App/             WPF UI, tray menu, diagnostics window
  Switcher.Core/            settings, heuristics, dictionaries, layout mapping
  Switcher.Engine/          keyboard hook, auto mode, safe mode, exclusions
  Switcher.Infrastructure/  Win32 interop, UIA/native adapters, input replacement
  Switcher.TestTarget/      manual test app
tests/
  Switcher.Core.Tests/      heuristics and layout mapping tests
  Switcher.Engine.Tests/    runtime-path and input simulation tests

Security / Privacy Notes

• The app does not require cloud services
• The app does not use API tokens
• Settings and optional diagnostics logs are stored locally under %APPDATA%\Switcher
• Diagnostics are intended for troubleshooting, not for capturing full documents

License

MIT