[Herby Herve]

Got it!!
I paste the script below.
I’m pretty sure that this script can be improved but it already does the job…

function hideLayer (layer, selectedLanguage){
// Hide/Show layers according to the last 2 digits of layer's name
if (layer.hasVideo && selectedLanguage == "All" || layer.name.slice(-2) == selectedLanguage){layer.enabled = true};
else {layer.enabled = false};
if (layer.hasAudio && selectedLanguage == "All" || layer.name.slice(-2) == selectedLanguage){layer.audioEnabled = true};
else {layer.audioEnabled = false};
// For layers used both in EN & FR version
if (layer.name.slice(-5) == "EN/FR" && selectedLanguage == "EN" && layer.hasVideo){layer.enabled = true};
if (layer.name.slice(-5) == "EN/FR" && selectedLanguage == "EN" && layer.hasAudio){layer.audioEnabled = true};
if (layer.name.slice(-5) == "EN/FR" && selectedLanguage == "CH" && layer.hasVideo){layer.enabled = false};
if (layer.name.slice(-5) == "EN/FR" && selectedLanguage == "CH" && layer.hasAudio){layer.audioEnabled = false};
};
// Scan all layers
function goThroughLayers (Comp, selectedLanguage){
for (var p = 1; p <= Comp.numLayers; p++){
// Check if layer needs to be modified
if(Comp.layer(p).name.slice(-2) == "EN" || Comp.layer(p).name.slice(-2) == "FR" || Comp.layer(p).name.slice(-2) == "CH"){
hideLayer(Comp.layer(p), selectedLanguage);
};
};
};

//UI
var w =new Window ("dialog","Select language");
w.orientation="column";
var radio_group = w.add ("panel");
radio_group.orientation="row";
radio_group.alignChildren ="center";
radio_group.add ("radiobutton", undefined, "EN");
radio_group.add ("radiobutton", undefined, "FR");
radio_group.add ("radiobutton", undefined, "CH");
radio_group.add ("radiobutton", undefined, "All");
var button_group = w.add ("group");
button_group.orientation="row";
button_group.alignChildren ="center";
button_group.add ("button", undefined, "Cancel");
button_group.add ("button", undefined, "OK");

// set dialog defaults
radio_group.children[0].value =true;

if(w.show ()== 1){
// Get selected language
for(var x = 0; x < radio_group.children.length; x++){
if(radio_group.children[x].value ==true){var selectedLanguage = (radio_group.children[x].text)};
};

app.beginUndoGroup("Language selection");

// Search for all Compositions in the project
for (var i = 1; i <= app.project.numItems; i++) {
if (app.project.item(i) instanceof CompItem) {
var Comp = app.project.item(i);
goThroughLayers(Comp, selectedLanguage);
}
}
app.endUndoGroup();
};


[Herby Herve]

Thanks Xavier. This helps a lot.
In the meantime, I’ve found this page where I found a lot of help as well: https://leemscripts.tumblr.com/
The last script on the page (enable 3d switches for an entire hierarchy) is quite similar to what I want to do.

More than enough to start this script. I’ll post news here…