Not able to edit some language strings

I know that translation projects are not always 100% complete, but I thought it should be able to edit every language string manually. Or am I wrong?

However, I believe it is not always possible to find the right language string at this moment. For example, in CB Invite I expect a language string for the text 'body' that appears on the screen when the user writes his personal message to his invited guest. In my Dutch language package the word 'body' has not been translated yet, so I want to do it by myself. But I can not find the right language string by searching for 'body'.

What should I do to change the word 'body' in my installation?

I have also some other examples (especially in CB Activity), but I first want to learn from the example described above.

You can add custom translations using language overrides functionality shown below.

www.joomlapolis.com/blog/kyle/18701-language-overrides-have-arrived

It has a built in language finder as shown below.

www.joomlapolis.com/blog/kyle/18712-language-key-and-text-finder

I also recommend anyone with the skill or time that is already translating incomplete languages to consider contributing to the localization project for that language. You can find out more info below.

www.joomlapolis.com/localization

I know how language strings work and I have already made some succesful changes. However, my problem is that I can not find a language string for 'body', although it should exist to my believe. When I search with key = 'body' some language strings appear, but not the right one. So I am not able to translate 'body' into a userfriendly, Dutch word. The string 'body' is just an example, because I have difficulties with some more strings.

You're likely experiencing the below bug.

forge.joomlapolis.com/issues/7432

If the backend language is the same language as the language plugin you're editing the language finder ends up missing the default language strings causing the language finder to fail in some cases. The workaround is to switch backend to English or use the language finder on the default language plugin to find a language key.

I have used language finder on the default language plugin to find a language key. Unfortunately, this makes no difference. I do not understand why important language strings are not in my system. E.g. 'What's on your mind' (from CB Activity) can not be found by language finder.

Switch your backend language to English and see if it works fine then. Beyond the above known bug there's no other known issues with the language finder.