Lack of verbal communication is problematic in many situations such as producer-consumer relationships to romantic relationships.

There is at least one situation where lack of verbal communication is benefitial. That is, things that can potentially become food can’t usually talk with their eaters. If zebras can talk back to lions about their rights to live, maybe there would be a couple lions that choose to die from starvation. If lettuce starts protesting on their factory-made , destined lives, vegetarians who are anti-hurting animals wouldn’t be able to eat any fresh things. And personally, activist lettuce sounds so cool to me that I feel I would have to respect them even after their deaths.

So, maybe lack of verbal communication among different species helps sustain the natural system on this planet (to some degree, of course).