I've finally managed to make my own fix [Im so proud, remember my credits] for the problem where you launch your English-Polish version of Black Ops 2 and it says:
Could not load default assets 'fonts/720/consolefont' for asset type 'font'.
Basicly what is causing the problem is, that when you download the game from steam, the english language pack is not downlaoded with it, and therefore its just looping to find the files but fails.
Here is what I did step by step.
1. Opened steam, right clicked on Black Ops 2 and changed the language to 'Polish'.
2. When it have downloaded around 1-2% of the polish language, you change it back to english. It will still download the polish language, but the dropdown menu will bug and stuck on 'English'.
3. When the download is completed, open black ops 2 and see if the game works (in polish ofcourse).
4. Download this file and put the 3 txt files in (common/callofdutyblackopsII/) folder and copy the 'english' folder under 'zone' to its respective location in your black ops installation folder (common/callofdutyblackopsII/zone/)
5. Open the game and play!
I hope this work, please comment, and share this tutorial on other forums and sites such as the Steam community where people are ripping their hair off, also remember to give credits (even if you make a youtube video!)
- Sahand Solki