Hello @Mashoko
The requirements for residence permit 25b differ slightly from many other types of residence permits. Usually a particular permit has requirements X, Y, and Z and they must all be fulfilled in order for it to be issued.
25b is a permit that should be issued to a person with a Duldung who is considered to be 'sustainably integrated' (nachhaltig integriert). The legal text then goes on to state that such integration 'regularly requires' certain things, and then lists them. This means that generally a person has to fulfil all the requirements but exceptions can be made. An example would be if a person was heavily involved in their local community, volunteering with organisations etc. It is not enough that a person, for example, is a member of their local football club. They would have to be much more involved, like training the younger kids, organising competitions, attending meetings etc. over a longer period. Such engagement can be considered alternate proof of integration, meaning the authorities could accept it in place of the language requirement.
In most cases, however, the language will be required. Please note it is spoken German that is required, not the overall level including reading and writing. A certificate confirming this level of German is not strictly necessary. The Ausländerbehörde can also accept that a person has fulfilled this requirement if the person can speak comfortably in German at this level with the Ausländerbehörde.
Under certain circumstances the language requirement can be waived altogether. This is if it is not possible for the person to learn German to this level for reasons of illness, disability or old-age.
Best,
Éanna