aakk9999 - 2:46 am on May 8, 2012 (gmt 0)
When changing Google.com to view another country results, you must also watch the "home language" (hl= parameter in URL).
If you view non-english speaking country, then most of google.com users will have their home language set to their own language (e.g. for germany hl=de). Google.com with hl=de and with hl=en from Germany IP will give different results.
You can also play with gl= parameter (geografic location) and setting this to something will again change the results.
I did find that if you have strong site and if the word/phrase searched for is the same in both languages, you will see less (or almost no) fluctuations in ranking.