quietschen
to squeak
To produce a high-pitched, shrill, and often unpleasant sound, usually caused by friction.
Die Bremsen des alten Fahrrads quietschen bei jeder Bremsung.
The brakes on the old bicycle squeak every time he brakes.

to squeak / squeal
Loading your saved state.
to squeak
To produce a high-pitched, shrill, and often unpleasant sound, usually caused by friction.
Die Bremsen des alten Fahrrads quietschen bei jeder Bremsung.
The brakes on the old bicycle squeak every time he brakes.

'Quietschen' (to squeak/squeal) is an onomatopoeic word. This means the word itself imitates the sound it describes—a high-pitched, shrill sound.
Hörst du, wie die alte Schaukel quietscht?
Do you hear how the old swing squeaks?
You can tell whether a noise or a feeling is meant from the subject. When things 'quietschen' (squeak), such as brakes or doors, it is about a sound caused by friction. When people or animals 'quietschen' (squeal), they usually express joy or excitement.
Die Reifen quietschten, als das Auto scharf bremste.
The tires squealed when the car braked sharply.
This meaning is often connected with things that make noises through friction. Typical subjects are: the brakes, the tires, the door, the bed, or the shoes.
Die nassen Schuhe quietschen auf dem glatten Boden.
The wet shoes squeak on the smooth floor.
When 'quietschen' (to squeal) describes an emotion, the reason is often given with the preposition 'vor' + dative. Typical phrases are 'vor Freude quietschen' (to squeal with joy) or 'vor Vergnügen quietschen' (to squeal with delight).
Als sie das Geschenk sah, quietschte sie vor Freude.
When she saw the present, she squealed with joy.
to scream
'schreien' and 'quietschen' can both describe high-pitched, loud sounds. 'schreien' is used mainly for people when they get loud out of fear, pain, anger, or joy. 'quietschen' often describes a high-pitched, shrill sound caused by friction, for example with brakes, doors, or wheels. For people, 'quietschen' fits more with joy or excitement and often sounds less serious than 'schreien'. The words can be confused because both can be loud and high-pitched. Remember: 'schreien' is a loud voice, while 'quietschen' is usually a bright, sharp sound.

Vor der Kreuzung quietschten die Bremsen des Fahrrads.
Before the intersection, the bicycle's brakes squeaked.
Er schreit, wenn die Ärztin die Wunde säubert.
He screams when the doctor cleans the wound.