Localization and tap gesture

> when I switxh language (inside the app),

Why do it that way? Why not let the device do that for you?

2 years later…

I finally found here inspiration here for something very close to what I wanted:
https://stackoverflow.com/questions/28152526/how-do-i-open-phone-settings-when-a-button-is-clicked

Button action to switch language:

Code Block 
    @objc func openSettings() {
        
        guard let settingsUrl = URL(string: UIApplication.openSettingsURLString) else { return }
        
        if UIApplication.shared.canOpenURL(settingsUrl) {
            UIApplication.shared.open(settingsUrl, completionHandler: nil)
        }
    }
    
    @IBAction func toggleLanguagePopover() {
        
        var languages : [Language] = []
        for country in Language.allLanguages {	// I have defined the list of languages the app is localised for
            languages.append(country)
        }
        
        var anAction : UIAlertAction
        var alertStyle = UIAlertController.Style.alert
        let alertController = UIAlertController(
            title: NSLocalizedString("Language", comment: ""),
            message: NSLocalizedString("Select a language, comment: "toggleLanguagePopover"), preferredStyle: alertStyle)   
        for i in 0..<languages.count { 
            anAction = UIAlertAction(title: languages[i].flag + " " + languages[i].fullname, style: .default, handler: { (action) -> Void in self.openSettings()} ) 
            anAction.isEnabled = Global.shared.systemLanguage != Language.allLanguages[i] // Button for the already selected language is disabled
            alertController.addAction(anAction)
        }
        
       let cancelAction = UIAlertAction(title: NSLocalizedString("Ok", comment: ""), style: .destructive, handler: nil) 
            alertController.addAction(cancelAction)
        present(alertController, animated: true, completion: nil)
    }

This brings you to the app settings page with direct access to preferred languages list.
Click on language and return to your app from the navigation button. You have switched the app language.

It's very fast.

Only caveat, the device language does not change, so settings remain displayed in device's language. But that's a really minor annoyance.