i think that adsense is really good! I want to known if I can write in spanish, because I can not speak english.
Yes, you can write your content in Spanish. Here's a list of languages that Adsense supports: Arabic Bulgarian Chinese (simplified) Chinese (traditional) Croatian Czech Danish Dutch English Finnish French German Greek Hebrew Hungarian Italian Japanese Korean Latvian Lithuanian Norwegian Polish Portuguese Romanian Russian Serbian Slovak Spanish Swedish Thai Turkish Ukranian -Source Hope this helps. Thanks
Adense CPM may be lower in other countries outside the States or even for other languages but you will have a better chance of competing. Rather make less money more frequently than more money once in a while (if ever). Stay with the language you know, a country you are familiar with and a topic that interests you. Focus on your content. The Adsense earnings will come.