But alas, de ar inte mina riktiga foraldrar.
Alas = ack :D
Jag såg vad du gjorde där! :P
is it -a because "they" is plural?
De is pronounced dom? Is there a reason?
That's the way we say it.
Not as far as I know.
If there is, it doesn't affect anything else other than "De" and "Dem", which are both pronounced "Dom".
In Finland Swedish 'de' is dee and 'dem' is 'dem'.
Vowel shifts tend to happen over centuries. (I can't explain the "m", though; perhaps a merger with "dem"?) This is just one of the few cases where Swedish spelling doesn't reflect modern pronunciation.
I think its just easier to say