Well, me again!
Sincerely, it can be the 2023 most favourite mod in my mind.
With my commitment in the 1st issue, I am glad to provide translation for it.
Here is the lang zh_cn:
zh_cn.json
It can work on mod version 1.4.2 to 1.5.0.3.

I've also translated the guide book. For few reasons, it cuts into 2 parts, datapack and resourcepack. It requires you put it all into right place. Datapack(guide book for zh_cn): Unusual Prehistory Encyclopedia v1.2.zip Resourcepack(guide book for zh_cn): Unusual Prehistory (zh_cn) v1.2.zip Reloading everything, it will work correctly.

SOMETHING TO TALK ABOUT IT:
Well, the book's json settings were placed in asset before, but now in data. This made me fail to build a complete package for the Encyclopedia. How about put it back?:D

There're a few plants haven't been added in :
anostylostroma(clathrodictyon's bro), zuloagae.

By the way, not just translating, I've beautify the UI of Encyclopedia.(but it's based on zh_cn's composing, means cannot be used in other edition:( )
(sample):

In this part, I've turned the copywriting into an original way(like dairy or list, for example gigantopithicus's trade),and I create some pics work with it.
However, this pics are generally sign of mine.
(sample):

If you don't allow me to keep my sign as a beatify symbol(Well, it sounds like asking for copyright permission), I'll cut this sign off.

Well, me again! Sincerely, it can be the 2023 most favourite mod in my mind. With my commitment in the 1st issue, I am glad to provide translation for it. Here is the lang zh_cn: zh_cn.json It can work on mod version 1.4.2 to 1.5.0.3.

ATTENTION：
As I working on it, I found some mistakes with en_us.(perhaps?)
"block.unusualprehistory.raptor_eggs"
"item.unusualprehistory.veloci_spawn_egg"
though it's from the same kind of animal, velociraptor has two performance in it. Maybe we can unify it?
"block.unusualprehistory.foxii_sapling"
"block.unusualprehistory.foxxi_wood"
...
foxxi's wooden things were named "foxxi", but only the sapling was written into "foxii".

I've also translated the guide book.
For few reasons, it cuts into 2 parts, datapack and resourcepack. It requires you put it all into right place.
Datapack(guide book for zh_cn):
Unusual Prehistory Encyclopedia v1.3.zip

Resourcepack(guide book for zh_cn):
Unusual Prehistory (zh_cn) v1.3.zip

Reloading everything, it will work correctly.