The language offers are based on the level of knowledge of the pupils. There are special preparatory classes at regular schools. The children change to the regular classes after successful language acquisition. There are schools where children take part in a regular class and attend additional language courses. Please ask about the offers in your specific case.
For adolescents who are already 16 years old and whose education in the country of origin would expect them to be able to obtain the middle school graduation or the General University Entrance Qualification, there are special two-year preparatory classes. This classes prepare pupils for a middle school qualification or the transition to upper secondary education.
In Hamburg, there is a full-day dual training preparation for new immigrant adolescent between the ages of 16 and 18 regardless of their residence status. After a input phase of several months, young people learn three days in the vocational school and two days in a company internship. At the same time, company integration assistants assist the young people and businesses. "AvM-Dual" is a two-year course in which young people can earn their first or middle school graduation (https://hibb.hamburg.de/bildungsangebote/berufsvorbereitung/berufsvorbereitungsschule/bildungsangebote-fuer-migrantinnen-und-migranten/).