You shouldn't need to do anything. From what I can gather, it uses a similar system to google's "Did you mean?" algorithm, which means it basically works for all languages (and also even for words like "derp" and "pwnage" which you would never expect to find in a regular dictionary)

So for example, if I type in "Jee suis de la France" it'll underline "Jee" and suggest "Je" as expected. I can then type "Jaig är från Sverige" in the exact same document and it'll underline "Jaig" and suggest "Jag" as expected.

I can even type in "pwnaige" and it'll suggest "pwnage"!!