The 'Reader' of read out loud pauses after each word for some documents.
It is not the issue of 'Read out loud', but of the document itself. The document creation is done such that the words appear like normal text in the pdf, but when the 'Reader' reads it, it appears to the 'Reader' as if each word is on a new line and it considers each word to be a new paragraph, hence, stops after each word. This is the reason for this bug (well, not actually a bug from your side).

Remedies might be:
1. The 'Reader' can be asked to check for such an issue and if it finds the entire document to be like this, then it can discard the newline characters and treat the words to form a sentence until the end-of-sentence is encountered.
2. Or you can just introduce a feature to select the duration of pause. If a user feels that the 'Reader' is pausing between words, they might choose to shorten the pause duration.

Hope to see it resolved soon.