Animals are divided into “articulate” and “inarticulate,” though not in the sense those words are generally used in Arabic. They are so called in the way that “silent” is said without misunderstanding for what is not at all silent, and “speaking” is said for what never raises its voice. Whereas people speak with each other when they come together, animals use bellowing, bleating, braying, neighing, yodeling, mooing, whooping, howling, barking, crowing, meowing, grunting, screeching, hissing, yelping, clucking, croaking, roaring, razzing, rattling and hissing.
There are other instances [of words, like "inarticulate," that have more than one antithesis], such as dhukūr which means “males” as opposed to females, like the merchants’ caravan [in its separation] from the women’s caravan. Dhikr [pl. dhukūr] is furthermore what we call “the upper-handed” of any two parties that come face to face or take [their leave?] of one another.
The articulate animal is the human being. Inarticulate is every animal whose voice is only understood by other members of its genus. We, I aver, understand many of the desires, needs and aims of the horse and the ass, the dog and the cat and the camel, just as we understand the desire of the baby in his cradle, knowing (and it is an exalted form of knowledge) that its crying signifies something different from what is signified by its laughter. Also we understand that the horse’s whinnying when it sees its feed-bag is different from its whinnying when it sees a mare, and that the cat’s call to the tomcat is different from her call to her young. And examples of this are many.
Human beings are articulate, even if they express themselves in the language of Persia or India or Greece. The Greek understands clear Arabic no better than an Arab understands the Greek's outlandish speech. In this sense, all people may be said to be “articulate.” When they say “inarticulate,” distinguishing it not from “articulate” but from “Arab,” they do not have this meaning in mind. Rather, they mean that the “inarticulate” man does not speak Arabic, and that an Arab cannot understand him. And Kuthayyir says:
Fa-būrika mā a'ta 'bnu Laylā bi-niyyatin
wa-sāmitu mā a'ta 'bnu Laylā wa-nātiquhu
In what Ibn Laylā gives off there is no way for you to learn his intention.
What Ibn Laylā gives out is of two kinds: silent, and vocal.
When they say: “He came bringing what is loud and what is silent,” the “silent” refers to [inanimate goods] like gold and silver, and the “loud” refers to any animal. Here it means he spoke, and fell silent. “Silent” refers to anything [in the way of capital] excluding live animals.
Considering what is in the world, we find its existence to be [the product of God’s] sagacity, and of [the products of] that sagacity we find two kinds: the thing that has no concept of sagacity or what it entails, and the thing that does conceive of sagacity and what it entails. The thing that conceives and the thing that has no concept are equally signs of [God’s] sagacity, but they are different from the standpoint that one is a sign that lacks the power of inference, and the other is a sign that has that power. As signs which lack the power of inference, animals (with the exception of people) are aligned with inanimate matter. To be a sign that also has the power to infer from signs was given to people. A connector was then made to be their guide to the various aspects of inference from signs and what results from inference. And that is what they call “intelligibility” [al-bayān].
The Book of Animals I 31-33