The way I interpret this is that those dialogues/voiceovers are Tav's (or Wyll's or anyone else's) interpretations rather than direct translations. The rather sophisticated syntax itself does not represent EXACTLY what the animals are trying to convey - there might/should even be subtle mistakes in those interpretations. I mostly like the "speak with animals" dialogues and their voice acting.
However, the semantics DO matter and there should be severe limitations to what the animals can actually say (regardless of 'how'). And there are some problematic examples: Volo's bear, the Druid Grove boar ("Halsin promised me a mate") and Topaz (the OCD bird with the coin) being the worst offenders I've found so far - I have checked their intelligence: 2, so nope, not Awakened. The Tieflings' rat is also questionable. The Druid Grove squirrel & Astarion's boar seem fine to me. Tingmiaq (the bird sent to look for Halsin) also has Int 2, though some birds (crows...) are actually VERY intelligent (though the whole intelligence comparison thing between humans and various animals is a bit flawed), so this might not be "unrealistic", but should probably be reflected in stats for us OCD people...
