Using the attached file, select all the text in the first textarea and instruct OSX to read it using the built-in Text to Speech system (Under settings, Dictation & Speech). The voice will only say "this is an ex", dropping the last part of the sentence. This seems to be a result of the textarea having collapsed whitespace characters within the value, as when the white-space value is changed to pre (in the second textarea), the voice will read the full sentence. This affects Safari Version 7.0.5 (9537.77.4) on OSX 10.9, and seems to affect some earlier versions as well.
<rdar://problem/17634593>
Created attachment 234739 [details] Reproduction HTML page