I have been using Android Studio in Spanish, and it bothers me that it highlights as incorrect words which are spelt correctly.
Can I add a Spanish dictionary to Android
Go into your Settings. Under "Language and Keyboard", go to and select "Android Keyboard" -> "Input language". Choose Spanish. That should do it!
Or, on Android 4, go to Settings -> Language & Keyboard -> Touch Input (settings button) -> Personal Dictionary -> Edit personal dictionary
The following link shows how to implement a spellchecker - you can implement this for multiple languages.