Why did Anderson think that "Rache" was German?

Question

In A Study in Pink the victim claws "Rache" into the floor before she dies. The forensic expert Anderson then suggests to Sherlock that it was German for "revenge". Sherlock then ignores this and says it was supposed to be "Rachel". Why doesn't Anderson make the same assumption?

There was nothing in the apartment to suggest that she was German and writing a name would be more common than writing a cryptic message in a different language so why did Anderson immediately jump to "revenge"?

(My theory: it's intended to make Sherlock look cleverer than the police)

Answer 1

A Study in Pink is BBC's adaptation of Sir Arthur Conan Doyle's A Study in Scarlet.

In the book, the German word "RACHE" was written in blood on the wall. Which means revenge.

So... that leaves us 2 possible answers:

1. Anderson never liked Sherlock until Sherlock faked his own death and Anderson kind of felt responsible how the things worked out. Before all that, Anderson hated Sherlock. So, in an attempt to look better than Sherlock, he tried to prove his German skills are better than anyone's. He probably thought about "Rache" meaning "Rachel" but you've gotta admit, if it would be really German word revenge, he would be something else in everyone's eye. Including Sherlock.

2. Back to the first statement of this answer. In the original book, it was really the German word revenge. As stated before, the TV version is an adaptation and the screen writers change a lot of things to make clever remarks about their intellect (my word to Steven Moffat and Mark Gatiss). So it was just a way to spice things up.

Answer 2

Well, there are 3 possible reasons for this:

1) Allusion

The makers Mark and Steven, in the entire series, have made several allusions as a tribute to the original works of A. C. Doyle. In A Study in Scarlet, Sherlock dismisses a suggestion that the victim was trying to write "Rachel", instead pointing out that "Rache" is German for "Revenge". In the episode this interpretation is reversed; he scoffs at the "Revenge" explanation and suggests the victim was trying to write "Rachel".

2) Prove Sherlock's Prowess

This is the very first episode of BBC's TV series. Hence, it is essential to prove how intellectually superior Sherlock is as compared to other ordinary people and highlight his chain of thought. When Sherlock walks into the room, he himself thinks of "Rache" being Revenge for a split second.

Then he dismisses this thought and arrives at RACHE(L).

3) Humour

It is pretty amusing to see Sherlock slamming the door in Anderson's face when he provided his insights.

Answer 3

Sherlock already has a bit of reputation with the police as someone who thinks outside the box and is inevitably right. Anderson, the professionally trained investigator, is rankled by the "amateur" Sherlock and wants to prove he is as capable of out of the box thinking - so he reaches for the "revenge" connection. This, as you point out, gives an opportunity for Sherlock to mock Anderson and show he is clever than the police.