My gf (american) claims it's "somebody else's" while I tend to think "somebody's else" is right. What do you think?
In modern English, genitive
's is a clitic that attaches to an entire noun phrase, as in example 1 below.
It doesn't attach to an individual noun, as in example 2:
1. [ The King of England ] 's pants
2. *The King's of England pants (ungrammatical)
The postmodifier else can attach to an indefinite pronoun like somebody, as in example 3 below.
It can't attach to a genitive noun phrase like somebody's, as in example 4:
3. [ somebody else ]
4. *[ somebody ] 's else (ungrammatical)
Since somebody else is a complete noun phrase,
's can attach to it:
5. [ somebody else ] 's
This is the correct choice.
"Somebody else" is a pronoun, and the possessive is formed by adding 's to the end of the pronoun: "somebody else's"
Google Books Ngram Viewer backs this up...
Summary of the results from the year 2000:
- "somebody else's": 4.9 x 10-6
- "somebody's else": 4.5 x 10-8
Furthermore, some of the matches for "somebody's else" don't really count... At least one match comes from a book written in 1894 with the following passage:
Would you say, Somebody else's or somebody's else?