@miguel_condesso well, you can continue with your old courses on one account and practice English from German on a different one. It might seem not very convenient to switch back and forth, but if you are doing it with the web app, you can log in to different accounts with different browsers or even with the same one with Firefox containers. It's much more difficult with a mobile app, but there are ways to clone it (at least on Android). To my knowledge, there is still no better option.
P.S. keep in mind, that if you are paying customer or if you decide to upgrade to Lingvist Unlimited for both accounts, it might lead to additional expenses.