Almost all text content in Dolphin depends on the language file, only a little is hard-coded in php files. Every piece of text comprises a language string or is a part of one. This language string in its turn has a language key which uniquely defines it. This means that you will most probably be able to change this content using Dolphin's Admin Panel:
1) Copy the text you want to edit. Sometimes you will have to copy only a part of the text because some text elements consist of two or more language strings.
2) Log into the Admin Panel and navigate to Settings -> Language Settings.
3) Paste the text you have copied in the field Search for strings and click any of the radio buttons and, or or exact sequence to broaden or narrow your search. You can even click on more settings to choose categories to search in. Then click on Search.
4) You will see the results that best correspond to your search criteria. They will be given for every language you installed. Now you will have to click on the edit link next to the language keys you wish to edit.
5) In the pop-up window which opens, you need to edit the String field, make sure that the checkbox Recompile corresponding language file to apply changes is ticked and then click on Save changes.