Articulate sounds are vocalizations that express

Express

-Communication:* Express , a series of Russian communications satellites* Express mail, a postal delivery service* Express , a free daily in Washington, D.C., U.S.* Daily Express, a British newspaper...

 the letters

Letter (alphabet)

A letter is a grapheme in an alphabetic system of writing, such as the Greek alphabet and its descendants. Letters compose phonemes and each phoneme represents a phone in the spoken form of the language....

, syllable

Syllable

A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...

s, etc, of any alphabet

Alphabet

An alphabet is a standard set of letters—basic written symbols or graphemes—each of which represents a phoneme in a spoken language, either as it exists now or as it was in the past. There are other systems, such as logographies, in which each character represents a word, morpheme, or semantic...

, or language

Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

. Non-humans cannot form articulate sounds, cannot articulate the sounds of their voice, excepting some few birds, as the parrot

Parrot

Parrots, also known as psittacines , are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropical regions. The order is subdivided into three families: the Psittacidae , the Cacatuidae and the Strigopidae...

, magpie

Magpie

Magpies are passerine birds of the crow family, Corvidae.In Europe, "magpie" is often used by English speakers as a synonym for the European Magpie, as there are no other magpies in Europe outside Iberia...

, Parakeet

Parakeet

Parakeet is a term for any one of a large number of unrelated small to medium sized species of parrot, that generally have long tail feathers...

, etc.

Articulate sounds are vocalizations that express the letters, syllables, etc, of any alphabet, or language. Non-humans cannot form articulate sounds, cannot articulate the sounds of their voice, excepting some few birds, as the parrot, magpie, Parakeet, etc.