Speech is the original form of linguistic communication, predating writing.

Evidence

The acoustic communication mode specific to human beings is speech. It is the original type of linguistic communication, substantially important for everyday life. Before the emergence of written language, speech was also a way to keep information alive through oral repetition, from one subject to another and from one generation to the next. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 538

Categorization

• DEFINE: Establishes that human-specific acoustic communication equates to speech, grounding the chapter.