I have a site that is replicated in many languages. The site itself display characters correctly but when viewing source the meta tags show the "unknown character" question mark instead of the foreign character.
What do I need to do differently for meta tags?
I have this tag already:
<meta http-equiv="content-type" content="application/xhtml+xml; charset=utf-8" />
I changed the charset to iso-8859-1 and it works now.
Then it means that you have saved the file as ISO-8859-1 (or possibly as CP-1252 when on windows) instead of UTF-8. In a bit decent text editor / IDE you should be able to configure the default file encoding and/or use the Save As option to set the desired encoding. Also, don't forget to set the HTTP response headers accordingly. How to do this depends on the webserver used and/or the server side language in question (if any).
By the way, you really don't want to use ISO-8859-1 when you want to go for World Domination. It doesn't cover all characters the world is aware of. It only covers Latin, not Hebrew, Cyrillic, Arabic, Chinese/Korean/Japanese, etc..etc..