German is famous for generating new words almost without limit, rarely borrowing from other languages, through two main mechanisms: composition (Komposition), which fuses two or more independent words into one new word, and derivation (Derivation), which adds suffixes or prefixes to an existing root. Mastering these two mechanisms unlocks thousands of compound or derived words without memorizing each one individually, because their meaning can be built up logically from their parts.
In composition, the decisive rule is that the last word in the chain determines both the grammatical gender and the core meaning of the whole compound, while everything before it functions like a modifier. der Schlüssel (key) attached to die Tür (door) does not give "door of the key" but der Türschlüssel — a key specifically for the door — taking the masculine gender of Schlüssel because it is the final element. This means the best strategy for decoding an unfamiliar long German word is to read it from right to left: identify the core word at the end first, then layer on the modifying meanings of the words preceding it. Even an intimidating word like Lebensversicherungsgesellschaft breaks down easily into Gesellschaft (company), specified by Versicherung (insurance), specified in turn by Leben (life) — a life insurance company.
Derivation works differently: suffixes such as -ung, -heit, -keit, -schaft, and -tion turn verbs or adjectives into nouns, and virtually all nouns produced this way are feminine — a rule reliable enough to trust without memorizing gender case by case. Prefixes such as ver-, ent-, be-, zer-, and er- attach to verbs and can shift meaning radically: kaufen ("to buy") becomes verkaufen ("to sell"); brechen ("to break") becomes zerbrechen ("to shatter completely"). Importantly, unlike separable prefixes such as auf- or mit-, these prefixes never detach from the verb and never take ge- in the Partizip II: verkauft, not geverkauft — a distinction many learners blur between separable and inseparable prefixes.
The other common mistake is trying to memorize every compound as an isolated unit rather than training the eye to decompose it into familiar parts — a skill that saves hours of vocabulary drilling and turns long words into a source of confidence rather than dread.