On "Fresh Air" Javier Bardem was asked what it was like to act in English and he said [this is the part where we pretend this is an actual quote when really it's just what I more or less remember. However, I don't think Javier reads this, so we're probably safe]:

"Even right now, as I'm trying to talk to you and express my opinions and thoughts and be relaxed, there is a very busy office full of people in my brain. They are working to make sure I get the right intonation, the right word.... It's exhausting.

When I speak Spanish, that office is closed."

I love that. As my French is used more and more seldom, the people in my office do not maintain any sort of regular schedule. Sometimes they're called in so unexpectedly that they are obliged to show up in their pajamas and then, man, do they have to scramble. That's probably why they can't guarantee the accuracy of the verb tenses.