https://developers.google.com/maps/documentation/javascript/localization?hl=en

By default, the Maps JavaScript API uses the user's preferred language setting as specified in the browser, when displaying textual information such as the names for controls, copyright notices, driving directions and labels on maps. In most cases, it's preferable to respect the browser setting. However, if you want the Maps JavaScript API to ignore the browser's language setting, you can force it to display information in a particular language by adding a language parameter to the <script> tag when loading the Maps JavaScript API code.

I'll make a PR for localization feature If you'd like it.