words are thoughts, and we cannot speak withou them. When we write we are revealing our thoughts, no matters which lenguage we use to do that and so happens way we speak.
Nevertheless, there aremany differences when it comes to write either spanish as a mother tongue or english and french as foreing lenguages; as a matter of personal opinion, I can find some differences when "I try to write" – and I swear I try- in in the three of them:

Language economic: writing in english allows me in, in few line of words,express something that in spanish could take even more lines. When I write in english I have the impression of being clearly understood, if I compare it to french.

diversity of expressions: when I write in french is more difficult for me to articulate the thoughts, however I can have the opportunity to be more descriptive thanks to the profusion of words that come to my maind like images.

Sheer confortability:when I write in spanish i feel more confortable with words, at the same time I feel I need many of them so I can be understood.