How can I change the language of the buttons in the Upsell Pop-ups?
You can change the language of the Product Page Pop-up and the Cart Page Pop-up in the Upsell settings. Open Upsell and navigate to Settings > Upsell Settings. In the Advanced Page Settings section, you can change the language of the Continue button, the No Thanks button, Add to Cart button, and more.
For more information, please visit the following link: https://support.boldcommerce.com/hc/en-us/articles/360043463172-Bold-Upsell-Settings