Technically, yes. Most (I cannot allege that "all") blog engines or programmes (that use PHP or RAILS) support multiple languages. The remaining question is: Who are your readers?
It is and isn't possible for someone to infect your blog with a virus. It is possible if they know how to edit your blog, using your username and password, so they could just imbed a virus to the webpage, but it isn't possible unless they can directly edit your blog.
Not possible. Answers.com is not a blog site, it is a question and answer site.If you already have a blog elsewhere you can put a link to it in your profile.
Yes it is possible to make money off your blog. If you have a personal blog this is usually done through advertising. You can also be paid to blog for a company or news organization.
Yes, it is possible for someone to have two first languages, known as being bilingual from birth.
You can't. It isn't possible (yet!).
"Joining" someone else's blog requires them to let other authors post their articles on his blog in the first place. Unless you mean "joining" a blog like "joining" a site as a member, which I don't think is possible.
The noun form of the adjective bilingual is bilingualism.
Bilingual means you can speak two languages so you become bilingual by learning another language.
Not that I'm aware of, bilingual says it best.
Bilingual is the correct spelling.
Someone who is bilingual knows two languages.
The word "bilingual" is an adjective.