Universal Translator

An offline, privacy-focused machine translation application for Linux built with GTK4 and the Bergamot translation engine.

The application is self-contained: the entire inference engine (Bergamot, Marian, SentencePiece, intgemm and ssplit) is compiled into a native library and linked into the Go binary via CGo. No translation is ever sent to a remote service. Models are stored in one of two places:

• ~/.cache/universal-translator/models/ are downloaded on demand by the app.
• /usr/share/universal-translator/models/ are system-wide, installed by the universal-translator-languages package.

Building

Requirements:

• Go 1.27+
• CMake 3.12+, Ninja
• GCC or Clang (C++17)
• GTK4 development headers (pkg-config gtk4)
• OpenBLAS (libopenblas) and PCRE2 development headers

Build:

make build;

This builds the native library under native/build/ and produces bin/universal-translator with bin/libbergamot_bridge.so alongside it.

Install system-wide (optional):

sudo make install;

Arch Linux users can build the two provided packages instead (packages/archlinux/):

# cd packages/archlinux/universal-translator
makepkg -si;

# in packages/archlinux/universal-translator-languages (bundles all models)
makepkg -si;

Usage

Run bin/universal-translator. Choose the source and target languages with the two dropdowns. If the required model is not installed yet it is downloaded automatically (with checksum verification), then loaded.

Type text in the left panel and press Translate; the result appears in the right panel. When no direct model exists for a pair, the app automatically pivots through English (e.g. Czech to English to German).

Layout

cmd/universal-translator/ application entry point and wiring
app/                     GTK4 user interface (MainWindow)
bindings/gtk/            hand-written CGo bindings for GTK4
adapters/bergamot/       CGo bridge to the native Bergamot C ABI
services/
  translator/            background worker owning the engine
  models/                language-pair resolution and model preparation
  downloading/           HTTP download with SHA-256 verification
repositories/            on-disk model store (cache + system-wide)
models/                  embedded catalogs (Bergamot + Firefox Translations)
types/                   shared value types
interfaces/              ports (ModelStore, Downloader)
caches/                  XDG cache path resolution
native/
  bridge/                thin extern "C" ABI over Bergamot
  third_party/           vendored Bergamot/Marian/SentencePiece/intgemm/ssplit
scripts/                 catalog generation tooling
dist/                    desktop entry
packages/archlinux/      Arch Linux PKGBUILDs
docs/                    architecture and workflow documentation

Documentation

See docs/ for the architecture and workflows: the package layout and threading model, the native C++ bridge, the model system, and the Arch Linux packaging.

Native library

native/CMakeLists.txt builds a single libbergamot_bridge.so from the vendored C++ sources with a small extern "C" shim (native/bridge/).

The Go side only ever talks to this opaque-handle C ABI, never to C++ types directly.

Tests

make test        # unit tests (no network, no model download)
make test-e2e    # end-to-end translation (downloads models)

License

GPL 3.0 or later