What is だって when it's at the beginning of a sentence?


I have read several definitions of だって but none of them seem to make sense
when I see it at the beginning of a sentence and I read the context. I saw one
example Japanese sentence and in the English translation だって wasn't translated
into anything.

So what is だって when it's at the beginning of a sentence?




Well, since I have no examples to go off of, I'll guess at which type of
scenario you're thinking of. It can mean like "But" or "Well (then)" in a kind
of defensive sort of way. Usually giving a reason for some action. Like
なぜかというと. Ex:

> お皿{さら}のものはみんな食{た}べなさい → Eat everything on your plate.  
>  だってお腹{なか}が一杯{いっぱい}なんだもん → But I'm full!

