Unwanted language keeps popping up in my keyboard languages

Since about a month ago Chinese language started popping up in my typing languages. I have 1 English and two Bulgarian languages if that's of any help. And when I go through them with alt+shift about once or twice a week Chinese comes there as well. I have no idea what brought this. When I go to the Input Languages it's not there. So I have to add it, apply, and then remove it in order to make it disappear from my language bar.
Any ideas on how to fix that?

Run a scan with malwarebytes and see what you come up with. Malwarebytes : Free anti-malware, anti-virus and spyware removal download Run a full scan after a complete update..

Just out of curiosity you haven't installed the Chinese language pack by mistake have you? You can check your update history in windows update to see..

http://www.sevenforums.com/tutorials/87313-display-language-packs-install-uninstall.html

Thanks for the response. I did a full scan after update with Malwarebytes, as you suggested, and didn't find anything. Then I did a scan with ESET Smart Security (the one I use for overall protection) and found two files with the same name f7d277e.exe in the Windows dir. It said it's an ad-ware. So it's deleted now and I'll see if that solved the problem.
And no, I don't have any other language pack installed other than English . I'll write again if I see CH in the language bar again.
Thanks again.

No, it's not fixed. It just came up again. Any other ideas?
Sorry for the double post, but I wanted to update the topic.

Check and see if you have any programs that you don't recognize and look in msconfig and see if their is something you also don't recognize starting up.
I would also run Super Anti Spyware.

Everything's the same way it's always been. Nothing new or unusual there.
PS: Super Anti Spyware found a bunch of tracking cookies but I don't think that's the root of the problem. I just now saw that this evening there were 5 updates to some Chinese dictionary as it says ??

4. sept. update:
It seems like the root of the problem was the Office proofing tools I had installed. I must have chosen bad settings when installing them. After the reinstall it's been ok. Thanks to you, who tried to help