Consider using synonyms or other words. For example the German word for performance, leistung, is already a few letters shorter. And you could drop the plurals. You can also opt to write words across two lines so you get talles but narrower tabs; squarish buttons are actually easier to press than narrow ones. If a combination of the above fixes the situation, perfect.
Trans- | Zu- | Leistung | Posten
aktion | teilung | |
If you still can't fit all tabs horizontally or the above solution is rejected for some reason (writers, brand guidelines etc), then you should go for one of 3 solutions depending on the amount of listed items.
few items: horizontally scrolling tabs
Scrolling tabs for 4 or 5 items of this size means users can access most tabs with 1 interaction, but if you have 8 or so items, people might have to scroll twice and then tap. If you have a clear priority for one or two items, put those first; it's better for discoverability and it saves clicks. But for the later tabs it gives worse discoverability and speed.
many options: traditional menu
Using an expanding menu means you always have 1 'wasted' intereraction to open up the menu, but when it is opened you have about 10~15 options available with the 2nd interaction. And of course you can make this a verticaly scrolling list for even more options but that's far outside the scope of your question. Users should be quite familiar with the general concept of a menu, and you don't risk people overlooking the last tab because they are new to scrolling tabs.
medium options - tabs and menu
The final possibility is a bit of a mix. Use 2 or 3 tabs for items with high priority and use a 3rd or 4th button to open a menu. This strikes a balance between speed of access and discoverability. It's also a bit better for clients that aren't very tech savvy because a button is more traditional than a scrolling bar of tabs.
The only thing to take in to account is that you need to have a certain amount of items in the menu. Even if you can fit [transaktion|zuteilung|performance|more…] on screen
I would instead put only [transaktion|zuteilung|more…] because it will really annoy people that they have to open a menu just to expand 1 button. Ideally you'd have 3 or 4 options in the menu.
There's a few factors to take in to account; discoverability, complexity, current paradigms, amount of required steps, user psychology... so it's hard to say which optiom works best without knowing more about the project, metrics, and customers. But I think the last option is the most safe option; more traditional interaction method, and room for a few more items in the list for future developments.