Excellent! Tested with English, Portuguese and Spanish.
Suggestion:
In Spanish and Portuguese, include an option to *globally* define the type of treatment that is intended: Informal or formal.

THIS APP IS VERY, VERY EXCELLENT AND SAFE...

Sehr zufrieden mit diesem Tool.

Muito bom. Já usava antes, via site. Agora, com a extensão, ficou ainda melhor!

Toujours un plus !

EXCELENTE GENIAL, EXTRAHORDINARIO.
FELICITACIONES

perfekt

Maravilhoso, vale cada centavo!

It recently started making the txt jump around when sending DMs in twitter rendering it unusable. Before that I preferred it to the more popular one

This is the best language tool out there for Portuguese, Spanish and English. As I've only used with these three, I can only review for them.