Now the title may be misleading, as I'm not going to have a pop at anyone
My Greek is not perfect but after 20 odd years in Greece I speak fluently, I even find myself thinking in Greek, while many times when I'm speaking English I have trouble coming up with an English word or phrase when the Greek one seems more relevant - you know, Gringlish.
But I've always noticed that when I'm tired I slip up on Greek words - can't find the right word, or can't get my tongue around it. Sometimes when I'm really tired I can hardly string two words together in Greek, literally I just can't pronounce them, and end up stopping mid sentence and speaking in English - to the amusement (or frustration) of some.
Is this normal ?? Well it could be - I've just read about the man trying to beat the world record for sleep deprivation (which stands at 11 days!!!) and he's now into his 8th day without sleep. The only physical sympton he has noticed is his speech becoming incomprehensible at times.
I know the feeling!