Screenreaders relate to text in some very specific ways.  For example, a paragraph is not signified by indentation but by a blank line between paragraphs.  Also, a sentence is a string of words that concludes with end-of-sentence punctuation followed by two spaces.  (End-of-sentence punctuation is a period, question mark, exclamation point or any of these combined with a single or double quotation mark.)

Word processors often have find-and-replace features with advanced options that will allow you to find the carriage return and tab that indicates the beginning of a paragraph visually and replace it with two carriage returns.  (In Microsoft word, search for “^p^t” and replace with “^p^p”.)  Similarly, a search can be performed that finds end-of-sentence punctuation followed by a single space and replaces it with the same punctuation mark followed by two spaces.  (For example, search for “. ” and replace it with “.  “)