How to translate subscribe process?

This is on write.as

The subscribe button can be translated and its colour can be changed.

The text above the subscribe button can be translated or like this

When clicking the subscribe button, “subscribing” is shown, how could this be translated or customized?

The confirmation message is “Please check your email and click the confirmation link to subscribe.” How could this be translated or customized?

When entering text which is not an email address, e popup shows “Please enter an email address”. How could this be translated or customized?

When subscribed, the message is “You’re subscribed to email updates. Unsubscribe”. How could this be translated or customized?

When unsubscribing, the message is “Unsubscribed. You will no longer receive these blog posts via email.” How could this be translated or customized?

Thanks!