Google has added an experimental feature in Google. This new feature is spellchecking in multiple languages at the same time. You can download the latest experimental Chrome Canary build to try this feature.
This feature is good for those who usually use words of multiple languages in the same message.
As this is experimental feature, you will have to enable this from chrome://flags/#enable-multilingual-spellchecker, you can now go to Google Chrome Settings languages at chrome://settings/languages and select every language of your choice in “Use this language for spell checking.”
It seems that the feature will not be available for Mac because it users OS’s language and settings for spell checking on Mac.