Are European video games in English?

It depends on the game and type of release.

Some games, especially those on a limited budget, will be released in each region or country group in a specific language, separately. Sometimes, the original language of the game plus an alternative will be the options. For example: English and German.

On the other hand, most bigger games with heavy budget behind them will include a language selection, either in-game or during the installation process, letting you choose what language you want to play the game in. This is known as Multi-X, where X is the number of languages the release includes. For example, a game that lets you choose between English, Spanish, German, French and Russian, would be known as Multi-5.