In case you want to change some common term used in Jive then you can use phrase substitution, which allows to change the key values from admin console.
Setp 1 -> go to <host>/admin/settings-phrases_input.jspa
2. -> click on View rules
3. -> add rule
4. -> set target dropdown to key
5. -> type the key and value for required locale
The alternate options are web/overlay changes to the keys or customise the i18n implementation classes (struts) for custom implementation or creating new keys and use them in custom views in themes in case you dont want to change jive's key values everywhere.