Speech coding is the most mature speech technology because it needs no databases.

Evidence

Speech coding is perhaps the most mature of the speech technologies. Very good speech quality can be obtained with low bit rates when signal models of speech production mechanisms are utilized. The methods are relatively simple, and no large databases are required. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2276

Categorization

• XREF: Relates to the book’s broader theme that model-based approaches beat data-hungry ones when a physical mechanism is understood.