When I experimented with phones I used the ones you mentioned.

But when it comes to industrial projects or commercial that should be a complete device... do not think of using a mobile phone. Instead look for a module like Telit if you can solder the extremely thin connector or a Siemens - Ericsson and more easy the Wavecom which has a VGA-15 connector.

Language is not a problem. I am not native speaking too.

Ioannis