I would have asked this in the comments, but my computer would let me add comments to things 99% of the time. Bad excuse, I know, but it's true.

Anyway, my question was: "can the ecard have English on it if it's not part of the lyrics, but the message itself?"

The Message in "Yellow" is NOT part of the lyrics. But does this count against the ecard?

Picture from WikiPedia

the Lyrics are by Me; about the future. It's called: "Future". The French version, I don't think translated very well.

Here's the Lyrics in English if you want to read them just highlight the hidden message. It's for fun...

The future is so distant, but yet it is so close
Can you hear it calling? It is calling out your name!
Please, let this message be known.
Please, don't ingore this sound.
Let it be heard! Let it be known!
Don't let the tears overflow our judgement
Don't let darkness blind your light
You can see, if only you want see, or deny destiny
Please, let this message be known.
Please, don't ingore this sound.
This voice inside is calling you on the outside, too.