"Porque" = "because" , "Por qué" = "why", I think in conversation "why" is often used instead of "because" but there is a pause and it is like a rhetorical question the person answers themselves. "Why?,it is too big." There is no question mark in "Porque es demasiado grande." , so stick with "because", Oh sorry I get what you are saying you, heard no difference. Yeah it might be hard to hear the difference. But the sentence with "Por qué" would have sounded a bit more like a question than a statement.
I completely agree, it should be easier to tell or at least accepted. However, whenever I hear a word and I'm not sure if its this or that (por que and porque being a great example), I use the turtle button to play it slowly. The slower audio separates each word, and should differentiate the two for you.
If your typo makes another word, it'll ding you no matter how tiny the typo was. Can't blame it for that, really - There's no way for the program to divine whether it was a typo or a vocabulary error at that point. I've been made aware of new vocabulary words this way, so it's not all bad!
"because it is very big" ... That could mean "too big" in the way that "very big" could mean "too big" in English, given the right context.
But, in general, "too" (in the sense of "too much", not "also") is "demasiado"; it's a good word to know and it's used often.
I specifically remember remarking one day, "Hace muy calor" and someone responding "demasiado".
DL gives a lot of choices for meanings of words. There are a couple of problems: 1. They don't let you know which one is best for that particular sentence; it's like looking it up in the dictionary. 2. Sometimes, the meaning for that sentence is not listed but you have to intuitively figure out how best to translate the word into English.
Anyway, I'm sure there are contexts where muy means "too". In most cases, though, muy is "very".
Native Spanish speakers, I'm open to corrections/additions.