The nominal style (Nominalstil) restructures a German sentence so that a verb which would otherwise sit in a subordinate clause becomes a noun derived from it, letting the whole subordinate clause collapse into a single noun phrase introduced by a preposition. Instead of Wenn man die Regeln nicht beachtet, gibt es Probleme ("If the rules aren't observed, there are problems"), you can say Bei Nichtbeachtung der Regeln gibt es Probleme — the subordinate clause disappears and is replaced by one noun, Nichtbeachtung.
This style is the backbone of formal, journalistic, scientific, and legal German. It gives a sentence brevity and objectivity by removing the impersonal subject man and shifting focus onto the action itself, treated as an abstract event rather than something someone does. Many languages already turn actions into things this way, using a verbal noun instead of a conjugated verb, so the underlying idea should feel familiar — what's new is the precise set of morphological rules German applies to build that noun.
The conversion follows three main patterns. First, the bare infinitive becomes a neuter noun simply by capitalizing it and adding the article das, with no change to the verb form: lesen becomes das Lesen ("reading"). Second, a feminine noun can be derived by adding the suffix -ung to the verb stem — the single most productive suffix in German — so prüfen becomes die Prüfung. Third, an agent noun is formed with -er for a male doer (der Lehrer) or -erin for a female doer. A handful of less regular suffixes also exist, such as -nis (Verständnis), -tum, and -heit, which simply have to be learned case by case.
Once formed, the noun is linked back into the main clause with a preposition signaling the temporal or causal relationship: bei, nach, vor, durch, and wegen are the most common, and each governs a specific case — usually dative with bei/nach/vor, genitive or dative with wegen/durch.
The most common mistake is keeping the full subordinate-clause structure — conjunction plus conjugated verb — and simply tacking a noun onto it, instead of deleting the conjugated verb entirely and replacing the whole clause with one noun doing the same job, which produces a doubled, unnatural sentence. A second frequent error is forgetting the gender of the derived noun, since a noun formed with -ung does not necessarily share the gender of a das + infinitive noun.