These words belong to the category of demonstrative pronouns (dieser) and indefinite determiners (jeder, mancher, welcher). They function similarly to articles and adjectives in sentences and follow adjective-like declension patterns.

Explanation

“dieser” (this,that,these,those)

„dieser“ is a demonstrative determiner (Demonstrativartikel) used to point to a specific person, thing, or idea that the speaker wants to emphasize or identify clearly. In English, it corresponds to this, that, these, or those, depending on the context. „dieser“ is placed before a noun when the speaker refers to a particular noun and wants to distinguish it from others or draw special attention to it, and its form changes according to the gender, number, and case of the noun (nominative, accusative, dative, genitive). 

Declension of “dieser”

Examples:

Dieser Mann ist mein Lehrer.
This man is my teacher.

Diese Blume ist sehr schön.
This flower is very beautiful.

Dieses Buch ist interessant.
This book is interesting.

Diese Studenten lernen Deutsch.
These students are learning German.

Ich mag diesen Film sehr.
I like this movie very much.

Er kauft diese Tasche.
He buys this bag.

Wir besuchen dieses Museum morgen.
We will visit this museum tomorrow.

Der Lehrer hilft diesem Schüler.
The teacher helps this student.

Sie spricht mit dieser Frau.
She speaks with this woman.

Wir spielen mit diesen Kindern im Park.
We play with these children in the park.

Die Farbe dieses Autos ist schwarz.
The color of this car is black.

Der Name dieser Stadt ist sehr bekannt.
The name of this city is very well known.

Die Meinung dieser Studenten ist wichtig.
The opinion of these students is important.

“jeder” (each/every)

“jeder” is an indefinite determiner (Indefinitartikel) used to refer to every single person or thing within a group, emphasizing that all members of the group are considered individually. In English, it corresponds to each or every. “jeder” is used only with singular nouns, although its meaning refers to all members of a group, and its form changes according to the gender and case of the noun (nominative, accusative, dative, genitive).

Declension of “jeder”

Examples:

Jeder Tag ist ein neuer Anfang.
Every day is a new beginning.

Jede Frau hat das Recht auf Bildung.
Every woman has the right to education.

Ich gebe jedem Schüler eine Aufgabe.
I give every student a task.

Das ist die Pflicht jedes Menschen.
That is every person’s duty.

Jeder Student muss die Prüfung schreiben.
Every student must take the exam.

Jede Blume im Garten ist schön.
Every flower in the garden is beautiful.

Jedes Kind braucht Liebe und Aufmerksamkeit.
Every child needs love and attention.

Der Lehrer spricht mit jedem Schüler.
The teacher speaks with every student.

Ich sehe jeden Tag meinen Freund.
I see my friend every day.

Sie hilft jeder Person, die Hilfe braucht.
She helps every person who needs help.

Der Name jedes Landes ist wichtig zu kennen.
The name of every country is important to know.

Der Lehrer gibt jedem Kind ein Buch.
The teacher gives every child a book.

Jede Stadt hat ihre eigene Geschichte.
Every city has its own history.

Jedes Problem hat eine Lösung.
Every problem has a solution.

“mancher” (some, many a, quite a few )

„mancher“ is an indefinite determiner (Indefinitartikel) used to refer to an unspecified number of people or things within a group, often suggesting that several or quite a few examples exist. In English, it corresponds to some, many a, or quite a few, depending on the context. „mancher“ is most commonly used with singular nouns and often carries a slightly formal or literary tone, emphasizing that something happens in a number of cases, even if the exact number is not specified.

Declension of “mancher”

Examples:

Mancher Mann ist klüger, als er aussieht.
Many a man is wiser than he appears.

Manche Frauen lieben Abenteuer.
Some women love adventure.

Ich habe mit manchem Freund gesprochen.
I have spoken with some friends.

Die Geschichte manches Landes ist faszinierend.
The history of some countries is fascinating.

Mancher Student versteht diese Regel nicht sofort.
Many a student does not understand this rule immediately.

Manche Menschen lernen sehr schnell.
Some people learn very quickly.

Manches Problem lässt sich leicht lösen.
Some problems can be solved easily.

Manchem Kind fällt Mathematik schwer.
Some children find mathematics difficult.

Manche Lehrer erklären Grammatik sehr klar.
Some teachers explain grammar very clearly.

Mancher Reisende entdeckt neue Kulturen.
Many a traveler discovers new cultures.

Manches Buch verändert unser Denken.
Some books change our way of thinking.

Manche Städte sind sehr alt.
Some cities are very old.

Mancher Besucher kommt jedes Jahr zurück.
Many a visitor returns every year.

Manchem Schüler fehlt die Motivation zu lernen.
Some students lack the motivation to study.

“welcher” (which)

„welcher“ is an interrogative determiner (Frageartikel) used to ask about a specific person or thing within a known or limited group of options. It helps the speaker identify or choose one particular item among several possibilities. In English, it corresponds to which. Like articles and other determiners in German, „welcher“ changes its form according to the gender, number, and case of the noun it refers to (Nominativ, Akkusativ, Dativ, Genitiv).

Declension of “welcher”

Examples:

Welcher Film hat dir gefallen?
Which movie did you like?

Welche Farbe findest du schön?
Which color do you find beautiful?

Mit welchem Freund gehst du ins Kino?
With which friend are you going to the cinema?

Die Geschichte welches Landes interessiert dich?
The history of which country interests you?

Welcher Lehrer unterrichtet Deutsch?
Which teacher teaches German?

Welche Stadt möchtest du besuchen?
Which city would you like to visit?

Welches Buch liest du gerade?
Which book are you reading right now?

Welche Studenten kommen aus Deutschland?
Which students come from Germany?

Welchen Film wollen wir heute sehen?
Which movie do we want to watch today?

Welchen Weg sollen wir nehmen?
Which way should we take?

Mit welchem Auto fährt er zur Arbeit?
With which car does he drive to work?

Zu welchem Zeitpunkt beginnt der Unterricht?
At which time does the lesson begin?

Der Name welches Schauspielers ist dir bekannt?
The name of which actor is familiar to you?

Die Kultur welcher Länder möchtest du kennenlernen?
The culture of which countries would you like to get to know?