OOTP question: Tonks & 'Wotcher'

[xpectopatronum]

No: HPFGUIDX 62447

Just a quick question -
Tonks keeps saying 'Wotcher'. What does it mean?
I find it interesting that JKR included this, as a part of her
character. Becuase, although she can change her physical appearance at
will, 'Wotcher' is something that she is known for saying, so it is a
way of seeing through her disguise...
I think jkr is slowly getting to something here.
Tonks is a young Auror. She could still be turned by Voldemort, OR,
perhaps even one of Voldemorts spies at the Ministry might also notice
what I've noticed.
What do you all think?

Cindy