The language used in Rocket League can be changed on each platform.

Epic Games Store

Open the Epic Games Launcher

Click on the Profile Icon (the first letter of your user name) in the right upper corner.

Select Settings.

Click on Rocket League.

Check the Additional Command Line Arguments box.

type: -language=xxx

xxx - replace this with the 3-letter code for your language

English - INT

French - FRA

Italian - ITA

German - DEU

Spanish (LATAM) - ESN

Dutch - DUT

Brazilian Portuguese - PTB

Japanese - JPN

Korean - KOR

Turkish - TRK

Russian - RUS

Polish - POL

Playstation

Go to your Playstation Dashboard.

Select Settings (located on the top right).

Select System Language.

Select your desired language.

Xbox

Press the Guide button on your controller.

Go to Settings.

Select System Settings.

Select Console Settings.

Select Language and Locale.

Select Language.

Select your desired language.

Nintendo Switch

Go to the Home Menu.

Select System Settings.

Select System.

Select Language.

Select your desired language.

Steam

Click Library.

Find Rocket League in the left-hand column list.

Right-click Rocket League.

Select Properties.

Select the Language tab.

Select the language from the drop-down menu.

Click the OK button.