If the text only look distorted or strange when on screen, but prints out fine, then this may be an indication that the text has been 'outlined'. In order words, the text is now a graphic comprising of filled in lines. Very often this will be more apparent on the 'L' or 'l' characters. One way to confirm this is to try and select the text with the Selection Tool (Black arrow). If you fail then the text is no longer font based and is simple a graphic.
This can be caused by many factors. It can be done by choice by certain applications to avoid missing fonts e.g. Selecting text in Adobe Illustrator and choosing Create Outlines. Very often this is done by graphic designers when sending layouts to printers to avoid missing fonts
This can also be caused by font issues such as Microsoft Office sometimes having problems with the font Arial Black when generating PDF's.
This can be caused in AutoCAD by changing the width factor of text from the default 1.0. It can also be caused by specifying the default PDF Graphic output in AutoCAD as 'TrueType Text ' instead of 'TrueType Text '.