The DreamHost panel automatically changes its language based on the locale value set in your browser. This is usually set by the operating system you're using, so there's nothing you need to adjust. The following link provides further information.
You are also able to manually change the language in the DreamHost panel if necessary as shown below.
Changing the panel language
- Log into your DreamHost panel.
- On the top right, click your username icon.
- From the dropdown, click the Language dropdown and choose either English or Spanish.