Is there a standardized version of Pali Patimokkha to be memorized?
Is there a difference in the recital of the Pali Patimokkha among the monks?
For a Pali recital of the Bhikkhu Patimokkha, together with romanized Pali subtitles, please see this Youtube video by Ven. Ariyadhammika. The pronunciation here is perfectly clear.
Please see the book Analysis of the Patimokkha by Ven. Nanatusita for the romanized Pali version, a translation of each rule and a word-by-word analysis. There are online versions here and here.
For a romanized Pali version of the Patimokkha without the translation, please see Bhikkhupātimokkhapāḷi compiled by Ven. Anandajoti.
An English translation by Ven. Thanissaro can be found here: Bhikkhu Pāṭimokkha: The Bhikkhus' Code of Discipline.
It's pretty well standardised, bar perhaps the normal - usually minor - differences in different countries' recensions.
The difference between different communities is the accepted style of recitation - speed and intonation the main variables - as well as interpretations over correct pronunciation.