The way you indicate is the right one if you have the phone connected to a UC500 with old firmware, so good. The other procedure works when the unit is connected to a third party call server, using SIP call control.
With latest version of UC500 and CCA (2.2.1), you can configure the language on SPA500 and SPA525G.
Configure Multicast Paging on the Cisco IP Phone 7800 Series or 8800 Series Multiplatform Phone
The Cisco IP Phone 7800 and 8800 Series Multiplatform Phones provide voice communication over an Internet Protocol (IP) network...
Add Call Park on a Cisco 7800 or 8800 Series Multiplatform Phone Key Expansion Module
Call park allows the user of the phone to put an incoming call on hold so that the call can be retrieved on another phone. A call is park...