Pronunciation of Tang Dynasty Poetry
well,  this answer is "limited" only, in relation to poetry in 唐 dynasty &amp; cantonese.

1   cantonese (and several southern dialects/languages) is highly correlated to middle chinese, which was used in 唐 dynasty.

2   cantonese still has 入聲 (entering tone), while mandarin lost it. e.g.

屋 uk1　sound file

沃 yuk1　sound file

燭 juk1　sound file

in mandarin, these three are pronounced as:

屋　wū　(陰平, dark level)

沃　wò　(去, departing)

燭　zhú　(陽平, dark level)

3   韻書 (rime dictionary), e.g. 切韻, 廣韻; one can find character based on cantonese, or other southern dialects / languages, but not mandarin.

4   poetry in 唐 dynasty had rules and patterns. compare to a language without entering tone, characters not in accord with rime dictionary; cantonese is a better choice.

last, there was a book 文鏡秘府論 by japanese monk 遍照金剛　(空海), which was written at about 809. it talks about the rules /  patterns of poetry &amp; chinese phonology in details. 

the internet archive has a copy:

https://archive.org/search.php?query=文鏡秘府論

or, 文鏡秘府論匯校彙考

have a read, please.