Internationalisation · Python · Linux

jalang — a bilingual desktop, built from gettext

An answer to "what if my whole operating system spoke two languages at once?" jalang merges Linux's translation catalogs into brand-new system locales so every menu, dialog and tooltip in GNOME reads as Primary (Bracket) — e.g. Lêer (File). Pure Python over the standard gettext toolchain, and it uninstalls as cleanly as it installs.

Lêer (File) · Wysig (Edit) · Instellings (Settings)

▶ See it running Source on GitHub ↗

Python stdlib gettext · .po / .mo msgfmt / msgunfmt localedef GNOME desktop Reversible

The bilingual desktop

Pick the generated locale in Settings → Region & Language, log back in, and the entire GNOME shell renders every string as Primary (Bracket) at once — read your interface in one tongue while absorbing another by osmosis.

jalang: the GNOME desktop rendering every UI string as Primary (Bracket)

Built & run live: Japanese (Afrikaans), French (English), Greek (Afrikaans) Read the build scripts ↗

Overview

Most software speaks one language at a time. jalang asks a stranger question: can the desktop speak two — at once, in every string — so you read your interface in one tongue while learning another by osmosis? The answer is a build tool, build_langpack.py PRIMARY BRACKET OUTCODE, that fuses two of the system's existing gettext catalogs into one and registers it as a fresh, selectable system locale. Pick it in Settings, log back in, and the entire GNOME shell is suddenly bilingual.

What's in it

🧩 A catalog merger

Each compiled .mo is unpacked, parsed, and recombined string-by-string into primary (bracket) — preserving the leading/trailing newlines msgfmt's strict check insists on.

🗂 Two trees, unioned

Ubuntu hides translations in two places — /usr/share/locale and the langpack overlay. jalang unions both, or the whole shell (GTK, nautilus, gnome-shell) is left untranslated.

🏷 Brand-new locales

Each pack ships as its own locale code chosen for a tidy display name — "Japanese (South Africa)", "French (United Kingdom)" — generated with localedef and registered in SUPPORTED.

↩ Clean reversal

An uninstall.sh tears out the merged trees, generated locales and registry lines and resets the display language — the experiment leaves no residue.

How it works

The merge: msgunfmt each .mo → a small PO parser → combine() joins the strings as primary (bracket), then msgfmt compiles the result back. When primary and bracket are identical (untranslated upstream) the bracket is dropped, so you never see File (File).
The bracket source: the bracket can be any installed language or the literal SOURCE — meaning "use the original English msgid" — so Afrikaans-primary packs still bracket nearly everything by falling back to English where no Afrikaans string exists.
Two catalog trees: the critical gotcha — Ubuntu splits translations across /usr/share/locale (upstream) and /usr/share/locale-langpack (the Ubuntu langpacks that actually hold GTK, GNOME Shell and nautilus). jalang overlays both.
Making it selectable: to surface in Settings → Region & Language a locale must be generated with localedef -i <src> -f UTF-8 <code>.UTF-8 and listed in /usr/share/i18n/SUPPORTED and /etc/locale.gen — verified against GNOME's own locale enumeration.
Additive & safe: merged catalogs live under their new locale code, leaving the original ja/fr/el/af catalogs untouched, and the whole thing reverses with one script.

Three packs were built and run live on the author's machine — Japanese (Afrikaans) across 768 domains, French (English) across 990, and Greek (Afrikaans) across 825 — then reverted. The build scripts stand on their own, so any primary × bracket combination can be regenerated on demand.

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