Originally the dinosaurs where not going to speak at all and the film was going to be a silent, slightly less kid-oriented, animated documentary with narration. At the last minute the studio hastily hired actors to voice the dinosaurs after the animation had been rendered which is why the dinosaur's mouths don't move when they speak and when they do the lip synching is off. After the film was released it was panned by critics with the main criticism being the awkward voice-overs.
Although the fact that small, raptor-like dinosaurs were feathered has been known since the end of the nineties, this is one of the first movies to actually depict many of its dinosaur characters with a feathery coat. Jurassic Park III (2001) was the first movie to feature raptors with any feathers at all. Originally, Disney's Dinosaur (2000) would also have included feathered raptors, but budget and animation issues forced the creators to depict them incorrectly with scales.
The tyrannosaurs in this movie are scaly because their models had already been completed before sufficient evidence - such as the discovery of the giant feathered Yutyrannus - came to light in support of the idea that these animals may have been feathered in real life, but also probably because the creators felt that the public would be more accepting of the traditional, scaly look, which is now known to have been incorrect.
The dinosaur Edmontonia isn't identified by name because the executives at Fox were afraid that viewers would confuse it with the similarly named Edmontosaurus. Instead, Edmontonia is referred to as an ankylosaur, which is the name for a broader group of dinosaurs that it belonged to. However, since unlike English, many languages don't differentiate between the "-saur" and "-saurus" suffixes, this consequently means that in some foreign language dubs, the animal is called Ankylosaurus. This, however, is incorrect, as Ankylosaurus, though itself an ankylosaur, was a totally different animal from Edmontonia.
A study released in December 2013, literally days before the movie was set to premiere, revealed that the dinosaur Edmontosaurus had a sort of fleshy wattle or comb on its head in real life. The movie's models, of course, lack this feature.
Character designer David Krentz is a big name in dinosaur modeling. He has also worked as the lead character designer and dino-sculptor in Disney's Dinosaur (2000) and the Discovery Channel's Dinosaur Revolution (2011). Interestingly, those projects have met a similar fate as this movie, as they were likewise originally meant to be silent productions with the animals' actions telling the stories, but were later given intrusive voices or narration at the request of the executives.
The movie has many similarities with the documentary film March of the Dinosaurs (2011), including taking place in the same general time and place (Cretaceous North America, 70 million years ago), depicting many of the same animals (Pachyrhinosaurus, Gorgosaurus, Edmontosaurus, Troodon, Edmontonia and Quetzalcoatlus), and focusing on a similar story with numerous similar set-pieces.