Issue with Language Pack Updates?

[Steve Grace]

I'm still fairly new to Ubuntu so please excuse me if I'm missing
something.

Last night I noticed that two security updates were available and
installed them. They were language-pack-en and language-pack-gnome-en. I
later noticed that some text in GNOME is now in UK English instead of
American English (I'm in the US). I've verified my language settings and
so am assuming that the language pack updates are responsible.

For example, the balloon text for the System menu now includes the word
"behaviour". I started from the Ubuntu live CD to confirm that this used
to read "behavior".

Is anyone aware of issues with the language pack update?

Can anyone in the US who's installed this update confirm the problem?

Thanks.

Steve