As described in Learning Klingon, the Klingon language is best read using a font with serifs such as Times New Roman. This font makes it easier to distinguish between a lowercase l and an uppercase I.

You can alter the appearance of a wiki by creating your own monobook.css. For further information see Wikipedia article on user style.

Your own monobook.css should contain this sort of entry:

body, #globalwrapper { font-family: serif; }