SEO for not english sites? experience, advice

I think it's absolutely necessary that you have someone that is a native speaker of the language (or extremely fluent) to do SEO on a legitimate site in another language. I say legitimate because if it's a churn n burn/spam site then it's a different story; spam is built on garbled content in English so why not crappy French content? Go to google translate and you'll be done in no time.

For a legitimate site though fluency is non-negotiable not only for content creation but for pretty much every aspect of SEO...

Take keyword research, my keyword research begins in my brain before I ever touch a tool. How can I begin if I can't "think" in that language? How will I do the job if I have no idea how a normal native speaker would be likely to phrase a search term? Picking the wrong keywords is throwing money down the Google toilet, so this is important to consider.

Fluency is necessary for backlinking too, what does that page you are dropping your link on really say? You can't trust Google to translate for you. Google isn't great with slang. There could be all kinds of nastiness or spam on that page that only a native speaker will understand. I know because I speak three languages myself, so I see what Google misses every day.

So... do you have a native speaker on your team? If so SEO in other languages is very similar to SEO in English for US sites. Onpage is the same and as long as you are within the "big ten" of languages used on the www you should have no trouble finding link opportunities: English, Chinese, Spanish, Japanese, Portugese, German, Arabic, French, Russian, Korean. (in that order)

If you go outside the big ten it's still possible, just make sure it's also profitable HTH

Google is Google, wherever in the world. SEO therefore is also the same.

But you may have to change your tactic. In countries with a smaller population than the US there are much less longtail keywords with a reasonable amount of searches. For enough traffic you may have to target single words and compete with the larger/older/stronger sites.

Another thing with smaller countries and lesser keywords is that you are more in a situation where everybody knows everybody. You are more in the open and when trying some blackhat SEO tricks there is a large chance of someone reporting you to Google.