Will Google’s “Panda” update affect non-English searches?
The short answer is Panda has been rolled it for most languages besides English:
For many months, we’ve been focused on trying to return high-quality sites to users. Earlier this year, we rolled out our “Panda” change for searches in English around the world. Today we’re continuing that effort by rolling out our algorithmic search improvements in different languages. Our scientific evaluation data show that this change improves our search quality across the board and the response to Panda from users has been very positive. Source
The only exceptions right now are Chinese, Japanese, and Korean, where Google continues testing for improvements. (In other words they haven’t got it right yet).
For sites that are affected by this algorithmic change, we have a post providing guidance on how Google searches for high-quality sites. We also have webmaster forums in many languages for publishers who wish to give additional feedback and get advice.