Lime survey comes with a few preconfigured label options for array style questions.
But if you want to apply custom labels in limesurvey, you can. You don't have to use the ones they provide.
Say you want a five point scale where 1 = "glum" and 5 = "peachy keen!"
The trick is that you can't cusomise the predefined array types.
Look at this list of array type question...
The plain "Array" question type (highlighted) is the only one that will accept custom labels. All the others already have custom labels applied and won't let you change them.
So make your question type a plain "Array", then save the question.
On the admin screen, click the "edit answer options for this question" button...
On the "Edit answer options" page, find (and click) the "Predefined label sets" button ...
This will bring up a list of custom labels sets which are available...
Choose the one you want, then click "Replace". Your question will now be updated with your custom label set...
(Note that this is how you apply or use custom labels. If you want to create new custom labels, see this article on label sets. )