 <p>One can do it exactly like in iOS: </p> <pre><code>let str = String.init(format: NSLocalizedString("TEST", comment:" "), 3) modularLargeTemplate.body1TextProvider = CLKSimpleTextProvider(text: str, shortText: str) </code></pre> <p>where the <code>Localizable.strings</code> file contains an entry </p> <pre><code>"TEST" = "Available: %i"; </code></pre> <p>This works, if <code>Localizable.strings</code> is target of the iOS app, and the watch extension.<br> However, I don’t know how to do the same with <code>CLKSimpleTextProvider.localizableTextProvider(withStringsFileTextKey: „TEST“)</code>.<br> Actually, I cannot imagine why a <code>localizableTextProvider</code> exists at all, if it cannot be used together with run time arguments (apparently), and does not provide any advantage (apparently) compared to the solution above.</p>