Which two phonetic branches are most related to physical sound production and properties?

The most relevant branches of phonetics concerning physical sound production and properties are articulatory and acoustic phonetics. Articulatory phonetics focuses on how sounds are produced by the movement of the speech organs, including the lungs, vocal cords, tongue, lips, and other articulators. This branch examines the physiological processes that create different speech sounds and how these are manipulated in speech production.

On the other hand, acoustic phonetics deals with the properties of sound waves produced during speech. It analyzes the physical characteristics of the sounds, such as frequency, amplitude, and duration. Acoustic measurements can provide insights into how different sounds are transmitted through the air and perceived by listeners.

Combining these two branches offers a comprehensive understanding of both how sounds are produced (articulatory) and how they are manifested as sound waves (acoustic), making them the most directly related to physical sound production and properties.