diff --git a/src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts b/src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts
index 313e55a10b5..2ea60014cde 100644
--- a/src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts
+++ b/src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts
@@ -677,7 +677,7 @@ export class WebExtensionsScannerService extends Disposable implements IWebExten
 			};
 		}
 
-		const packageNLSUri = webExtension.packageNLSUris?.get(Language.value());
+		const packageNLSUri = webExtension.packageNLSUris?.get(Language.value().toLowerCase());
 		if (packageNLSUri || webExtension.fallbackPackageNLSUri) {
 			manifest = packageNLSUri
 				? await this.translateManifest(manifest, packageNLSUri, webExtension.fallbackPackageNLSUri)