From the Huawei U8800 FAQ's Manual:
2.7 Language and Keyboard
2.7.1 How do I change the phone language?
Touch > Settings > Language & keyboard > Select language and select the phone language.
2.7.2 How will I do it if I am unable to select my desired language?
When your phone support for your desired language but you are unable to select the language on the phone, insert the SIM card of your desired language. Then, touch > Settings > Privacy > Factory data reset.
2.7.3 Why am I unable to use the input method after the input
software is successfully installed?
After installing an input software, you must check the input method:
Touch Settings > Language & keyboard and check the new input method.
I think that what they are trying to say, is that you must use the Firmware Upgrade (Download from huaweidevice.com ) and use your comp to put the Update onto the Micro SD card.
When you Download the correct Update for your phone model, you can extract and open/explore and you will find a Pdf file which you can print out. This gives the instuctions and procedure to follow to update your phone.
I don't think the SIM card has the Data on it. It normally has your Telco Provider info only. When I did a Factory Reset on a U8150 Ideos, it first gives you a choice of language (Chinese or English) which you use Vol buttons to scroll up or down and Power button to Enter.
Hopes this helps. Neil.