Is there a Chinese word to 'root' the phone, or is this universal tech speak?

Haha, thats what I was wondering, I just told him I needed to be able to delete all these apps, and he got what I meant... Even with my terrible Chinese :D

>>"Is there a Chinese word to 'root' the phone, or is this universal tech speak?"

Chinese use the same word for it, spelled with English letters.

Its universal body language. I went in and held my phone in front of me with both hands at arm's length and moved my groin back and forwards towards the phone while looking very pleased. They all understood what I wanted. They didn't help me root the phone, but they did send me to a place where I got what I wanted. :-)

Other dumb questions
If I buy a second hand iphone, and it is using Chinese language, is it reasonable to assume I can instantly change it (and any apps) to English language from a menu choice?

Are the phones independant of service provider? i.e. can I put my China Unicom SIM card in any iPhone?

Yes, with the iPhone it has a setting to change directly to English for all iPhone functions (settings etc). But it won't change the apps as the previous owner would have downloaded the Chinese version of the apps. If you want English language versions they will have to be re-downloaded (if available in English), or alternately the language might be able to be changed within the app. For example in WeChat I believe the language can be changed under settings.

Note that you may find it hard to download English language apps in China as it will likely link to the Chinese app store which is mostly in Chinese.

Yes.
Availability of apps also depend on which country's iTunes store you register from. You can change that by clicking on small Chinese flag at the bottom right of iTunes, and then regster.

If it's a Japanese iPhone you can't suibian change cards unless you pay for a remote unlock.

Can you re-register for US/UK?

If you want a completely new uk account, you can change the country flag in itunes and then use a new email address to register for a new account.
You can also change the country of you existing apple account. On ipad it's in settings, itunes options, then click on your id. It should be the same procedure for iphone i think. You'll then put your uk card details and address. If you don't don't have a US card but still want to download free apps only available on the US store, it's also possible to register for a new account without a card but still be able to get the free apps.

thx