macOS 15.4.1
Siril 1.4.0-beta 1
In general, the app follows my system language choice (English) but system dialogs come up in another language. Oddly, this includes the names of folders, like “Documenten” for “Documents”. I tried explicitly setting the language to English, but that didn’t help.
Hello. These are native filesdialogs that are linked to the operating system. That’s why Siril, and Gtk, have no control over the language or anything else.
I have never spoken any language but English in my 65 years, except for a brief stint with Spanish in high school. I’ve never installed any version of macOS or Windows in any language other than English. I’ve never had any app display any system dialogs in any language other than English. While these may be out of Siril’s and Gtk’s (whatever that is) control, they are broken and are using the wrong language. Note that 1.2.6, which also uses these uncontrollable system dialogs, displays them in English. It may not be obvious what mistake Siril is making, but it’s Siril making the mistake — hence the report.
Nope. It could be GTK issue, as1.2.6 and 1.4.0 have different GTK versions. But in Siril we really have no control over the native filedialogs.
So I’m sorry, but I really can’t help here 
Given that you’re not going to take any responsibility for even the possibility that this is a problem with your app and not a character flaw in each of your users, I’ve taken the liberty to work with ChatGPT to find a solution for you.
When launching Siril from the macOS Applications folder, system dialogs (such as “Open File”) appear in Dutch (e.g., “Annuleer”, “Verberg opties”) even though the system language is set to English.
This is a GTK issue, but it occurs because Siril’s macOS app bundle does not explicitly set the LANG or LC_ALL environment variable, so GTK defaults to another locale — likely based on a system or user regional setting unrelated to the UI language.
Steps to Reproduce:
1. Install Siril on macOS.
2. Launch Siril by double-clicking the .app in /Applications.
3. Observe that GTK dialogs (like file open/save) may appear in the wrong language (Dutch in this case).
Temporary Workaround:
Running Siril from Terminal like this resolves the issue:
LANG=en_US.UTF-8 open /Applications/Siril.app
Suggested Fix:
Set the appropriate locale variable (LANG or LC_ALL) within the app bundle, either:
• via setenv(“LANG”, “en_US.UTF-8”, 0); in code before GTK is initialized, or
• by adding a wrapper script that sets the environment variable before launching the app.
Alternatively, you could detect the preferred macOS UI language via defaults read -g AppleLocale and pass it to GTK for proper localization.
Hmmm.
Don’t think chatGPT has an answer for everything. Sorry but the LANG environment variable is well set. Siril can be configured for more than 10 languages.
And if you want to contribute, please feel free to open a MR.
I don’t know what a MR is and I wouldn’t know how to “contribute”. This is a beta version and I’m providing feedback on a bug in Siril that seems to affect everyone except Dutch speakers. If you are the developer of this app, it seems like it’s something you might be interested in knowing. But maybe not.