I'm afraid you can't. Even if you buy NewscasterVocalizer Global without the Standard Version, you will not be able to login.
Here is why:
1. NewscasterVocalizer Standard is the main product which is either an Yearly Subscription or Monthly Subscription.
2. NewscasterVocalizer Global is an Upgrade or Up-sell which enables Translation Feature in your NewscasterVocalizer account.
3. Since NewscasterVocalizer Global is not independent, you will need to subscribe for the main product NewscasterVocalizer yearly or monthly subscription first. Else you can't login with only NewscasterVocalizer Global in your account.