When you see a Submit button on a form, what comes to your mind? One could easily reason that clicking the button submits the user’s information into the system for processing. A Submit button describes what the system does well, but it doesn’t describe what the user does at all.
When users fill out a form, they are engaging in a task. The action button should affirm what that task is, so that users know exactly what happens when they click that button. A button that describes the user’s task tells users that the form focuses on carrying out that specific task. The more focused your form is, the more likely you’ll get users to complete your form.
via UX Movement – Why Your Form Buttons Should Never Say Submit. While submit describes a generic case of what the user is doing (ie. submitting a form) it doesn’t really help the user know what the button is for.