Fine distinctions with relative pronouns (was as relative pronoun, usage of deren/dessen)

Fine distinctions with relative pronouns in German: "was" as a relative pronoun and the use of "deren"/"dessen"

What is a relative clause and how do German relative pronouns work?

A relative clause (Relativsatz) gives extra information about a noun or a concept mentioned earlier (the antecedent). It is introduced by a relative pronoun. In German the usual relative pronouns are der/die/das (and their declined forms) or welcher/welche/welches. Two special topics that often confuse learners are when to use "was" as a relative pronoun, and how to use the genitive relative pronouns "deren" and "dessen".

Quick reminder about the normal relative pronouns
- German relative pronouns agree in gender and number with the antecedent but take the case required inside the relative clause.
- Forms (short overview):
- Masculine: nominative der | genitive dessen | dative dem | accusative den
- Feminine: nominative die | genitive deren | dative der | accusative die
- Neuter: nominative das | genitive dessen | dative dem | accusative das
- Plural: nominative die | genitive deren | dative denen | accusative die

Examples (normal relative pronoun):
- Der Mann, der dort steht, ist mein Bruder. (The man who is standing there is my brother.)
- Die Frau, die ich gestern gesehen habe, ist Ärztin. (The woman whom I saw yesterday is a doctor.)
- Das Kind, dem ich geholfen habe, lächelte. (The child to whom I gave help smiled.)
- Das Haus, dessen Fenster neu sind, gehört uns. (The house whose windows are new belongs to us.)

When do I use "was" as a relative pronoun?

German "was" is not interchangeable with der/die/das. There are specific antecedents and situations where "was" is the correct choice. Use "was" in these main cases:

1) After neuter demonstrative or nominalized "das" ("that which" / "what")
- Das, was er sagt, ist wichtig. — (What/That which he says is important.)
- Ich habe das getan, was nötig war. — (I did what was necessary.)

2) After indefinite pronouns and quantifiers such as alles, nichts, etwas, vieles, manches, wenig, einiges
- Alles, was du brauchst, liegt auf dem Tisch. — (Everything you need is on the table.)
- Nichts, was er sagte, überzeugte mich. — (Nothing he said convinced me.)
- Vieles, was im Internet steht, ist nicht überprüft. — (Many things that are on the internet are not verified.)
Note: With some indefinite words (especially "etwas") you may sometimes hear "das" instead of "was"; however, "was" after indefinites is very common and idiomatic.

3) After superlative or nominal phrases like "das Einzige", "das Beste", "das Wichtigste"
- Das Beste, was mir je passiert ist, war die Reise nach Prag. — (The best thing that ever happened to me was the trip to Prague.)
- Das Einzige, was zählt, ist Ehrlichkeit. — (The only thing that matters is honesty.)

Important restrictions with "was"
- "was" cannot refer back to a concrete noun phrase with a definite article or a modifying adjective. Wrong: *Die Frau, was gestern kam, ... — Correct: Die Frau, die gestern kam, ...
- "was" does not replace relative pronouns that refer to people. Use der/die/das (or wer/den/der etc. where appropriate) for people: Die Frau, die... / Der Mann, der...
- "was" is invariable (it does not change for case). If the relative pronoun inside the clause needs to show case other than nominative, you often cannot use "was".

Examples showing correct vs. incorrect usage
- Correct: Alles, was du brauchst, ist da. — (Everything you need is there.)
- Wrong: *Der Tisch, was auf dem Balkon steht, ist neu. — Correct: Der Tisch, der auf dem Balkon steht, ist neu. (Use "der" because the antecedent "der Tisch" is a concrete noun.)
- Correct: Das, was er sagte, war sinnvoll. — (That which he said was sensible.)
- Correct (people): Die Frau, die dort arbeitet, kommt aus Spanien. — (Use "die", not "was".)

How to use "deren" and "dessen" (the genitive relative pronouns)

"dessen" and "deren" are the genitive relative pronouns in German. They translate to English "whose" (possession) and point back to the possessor (the antecedent). The choice depends on the gender and number of the antecedent (not on the possessed noun).

Basic rule
- Use "dessen" when the antecedent is masculine singular or neuter singular.
- Use "deren" when the antecedent is feminine singular or plural.

Examples: masculine / neuter antecedent -> dessen
- Der Mann, dessen Auto gestohlen wurde, ist wütend. — (The man whose car was stolen is angry.)
- Das Buch, dessen Autor unbekannt ist, liegt auf dem Tisch. — (The book whose author is unknown is on the table.)

Examples: feminine / plural antecedent -> deren
- Die Frau, deren Hund laut bellt, ist meine Nachbarin. — (The woman whose dog barks loudly is my neighbor.)
- Die Kinder, deren Fahrräder gestohlen wurden, weinten. — (The children whose bicycles were stolen cried.)

Common learner errors with "deren"/"dessen"
- Mistake: matching the genitive pronoun to the gender of the possessed item. Example mistake: *Die Frau, dessen Sohn ... (wrong)
- Fix: The antecedent is "die Frau" (feminine), so use "deren": Die Frau, deren Sohn ...
- Mistake: using "dessen" when antecedent is plural. Example mistake: *Die Lehrer, dessen Klassen ... (wrong)
- Fix: antecedent is plural (die Lehrer) -> use "deren": Die Lehrer, deren Klassen ...

Usage notes and alternatives (register differences)
- "dessen" and "deren" are the natural, compact way to express English "whose" in standard and written German.
- In spoken or colloquial German people often avoid genitive constructions and rephrase using a dative structure plus a possessive pronoun. This changes the structure but keeps the meaning:
- Formal: Der Mann, dessen Auto gestohlen wurde, ist traurig.
- Colloquial alternative: Der Mann, dem sein Auto gestohlen wurde, ist traurig. (dative + his own = avoids genitive)
- Formal: Die Frauen, deren Autos beschädigt wurden, reklamieren.
- Colloquial: Die Frauen, denen ihre Autos beschädigt wurden, reklamieren.
- Both variants are common; the genitive forms are more typical in writing, while the dative + possessive is frequent in speech.

Common pitfalls and how to fix them

1. Using "was" for people or specific nouns
- Wrong: *Die Frau, was geholfen hat, ist nett.
- Correct: Die Frau, die geholfen hat, ist nett.

2. Using "was" when the antecedent is a definite noun phrase
- Wrong: *Das Buch, was auf dem Tisch liegt, ist neu.
- Correct: Das Buch, das auf dem Tisch liegt, ist neu.
- If the antecedent is the demonstrative "that" (das = "that which"), then: Das, was du sagst, ist wichtig.

3. Mixing up "deren" and "dessen"
- Wrong: *Die Frau, dessen Hund ... (here the antecedent is feminine)
- Correct: Die Frau, deren Hund ...
- Tip: Identify the antecedent first (who/what owns something), then pick "dessen" for masculine/neuter antecedents and "deren" for feminine/plural antecedents.

4. Forgetting that "was" does not show case
- If the relative pronoun needs to show a non-nominative role in the relative clause (like dative with a person), you normally cannot use "was". Instead use the appropriate der/die/das or restructure the sentence.
- Example: "Everything that I gave him ..." = Alles, was ich ihm gegeben habe ... (here "was" is fine), but for a person: "The friend to whom I gave the book ..." = Der Freund, dem ich das Buch gegeben habe, ... (use dative "dem", not "was").

Useful decision checklist (quick reference)

- Is the antecedent a person or a concrete noun phrase (with a determiner)? Use der/die/das (declined) or welcher/welche/welches.
- Example: Die Frau, die dort wohnt...
- Is the antecedent "alles", "nichts", "etwas", "vieles", "manches" or a superlative/"das Einzige"/"das Beste" or the neuter demonstrative/nominalized clause "das"? Consider "was".
- Example: Alles, was du brauchst... / Das Beste, was mir passieren konnte...
- Do you need to express possession (English "whose")? Use "dessen" (masc./neuter antecedent) or "deren" (feminine or plural antecedent). If this sounds awkward, you can rephrase using dative + possessive pronoun in speech.
- Example: Der Mann, dessen Auto ... / Die Frau, deren Hund ... / Der Mann, dem sein Auto ...

Extra example set (common patterns with translations)

- Alles, was glänzt, ist nicht Gold. — Everything that glitters is not gold.
- Das, was er gestern sagte, war überraschend. — What he said yesterday was surprising.
- Manches, was in der Zeitung steht, ist übertrieben. — Some things that are in the newspaper are exaggerated.
- Der Politiker, dessen Reden kontrovers sind, wurde interviewt. — The politician whose speeches are controversial was interviewed.
- Die Stadt, deren Geschichte interessant ist, zieht Touristen an. — The city whose history is interesting attracts tourists.
- Die Bücher, die auf dem Tisch liegen, gehören mir. — The books that are on the table belong to me.
- Ich kenne jemanden, der/deren Idee gut ist. — (If the person is male use "der", if female "die"). Example: Ich kenne eine Frau, deren Idee gut ist. — I know a woman whose idea is good.
- Der Lehrer, dem die Schüler zuhören, erklärt die Aufgabe. — The teacher whom the students listen to explains the task. (dative "dem")

Glossary (simple definitions)

- Antecedent: the word or phrase a relative clause refers back to (the noun that the relative clause describes).
- Relative pronoun: a word that introduces a relative clause (e.g., der/die/das, welcher, was).
- Genitive: the case expressing possession ("whose" in English). In German relative clauses, genitive forms include "dessen" and "deren".
- Indefinite pronoun: words like alles, etwas, nichts, vieles (not referring to a specific thing).

Summary

- Use "was" as a relative pronoun after neuter demonstrative/nominalized "das", after indefinites (alles, nichts, vieles, manches, etc.), after superlatives and when the antecedent is an abstract or whole clause. Do not use "was" for people or for specific definite noun phrases.
- Use "dessen" for masculine or neuter antecedents and "deren" for feminine or plural antecedents to express possession (English "whose"). These are genitive relative pronouns and are common in written and formal German. In speech, people often rephrase using dative + possessive pronoun (dem + sein / denen + ihre) to avoid the genitive.

If you want, I can now give a focused set of practice sentences with corrections and short explanations (answers included), or produce a printable one-page summary you can use as a quick reference.