Diction and style are two old standard Unix commands.
Diction identifies wordy and commonly misused phrases. Style analyses
surface characteristics of a document, including sentence length and
other readability measures.
These programs cannot help you structure a document well, but they can
help to avoid poor wording and compare the readability (not the
understandability!) of your documents with others.
Both commands support English and German documents.
Max Howell
Alexis Hildebrandt