The article refers to different "possibilities" of what will happen to the energy the wave is carrying. This is more about the treatment of the wave and its propagation. As Jacob Bach very well states in their comment, these three "possibilities" happen in pretty much all media.

Sound is a wave, as already stated in the article you quoted. This simply means that since we are dealing with a mechanical wave, the physical law governing waves should apply here. This is true (at least to a big extent) and sound exhibits many wave phenomena, in various degrees (some, such as dispersion in the air are negligible).

Regarding reflection and transmission, this is quite similar to the way this happens for light. In general, whenever a mechanical (this is true not only for mechanical waves) wave encounters a change in impedance of the medium then part of its energy (or conceptually you can think as part of the wave) is reflected, while part of its energy is transmitted "on the other side" of the interface where the mismatch occurs. For more information regarding reflection and transmission, you can refer to books like this, this or this. For a more "macroscopic" approach with additional information on the acoustical treatment of spaces, you can have a look at this book.

Now, regarding the "transformation" of sound energy to heat, in general, the main mechanisms this can happen are through heat conduction between the various parts of a wave (this is a non-reversible process) and viscosity (especially close to boundaries). These are (usually) called "classical attenuation" but they are not the only ways a sound wave can lose energy though. In the second book above as well as this book you can find a good explanation of the other mechanism that can introduce attenuation. This mechanism is encountered in the literature as "molecular attenuation" and is related to the different possibilities a multi-atomic gas can store motion energy (hence heat). The externally provided energy is stored in a translational movement initially. The process of distributing the energy given to the molecule by the external forces in all the different "possibilities" takes some time (relative to the molecular time scale) and is known as molecular relaxation.

The article refers to different "possibilities" of what will happen to the energy the wave is carrying. This is more about the treatment of the wave and its propagation. As Jacob Bach very well states in their comment, these three "possibilities" happen in pretty much all media.

Sound is a wave, as already stated in the article you quoted. This simply means that since we are dealing with a mechanical wave, the physical law governing waves should apply here. This is true (at least to a big extent) and sound exhibits many wave phenomena, in various degrees (some, such as dispersion in the air are negligible).

Regarding reflection and transmission, this is quite similar to the way this happens for light. In general, whenever a mechanical (this is true not only for mechanical waves) wave encounters a change in impedance of the medium then part of its energy (or conceptually you can think as part of the wave) is reflected, while part of its energy is transmitted "on the other side" of the interface where the mismatch occurs. For more information regarding reflection and transmission, you can refer to books like "Acoustics - A Textbook for Engineers and Physicists" by Jerry H. Ginsberg, "Fundamentals of Acoustics" by Lawrence E. Kinsler et al. or "The Foundations of Acoustics - Basic Mathematics and Basic Acoustics" by Eugen Skudrzyk. For a more "macroscopic" approach with additional information on the acoustical treatment of spaces, you can have a look at "Acoustic Absorbers and Diffusers - Theory, Design and Application" by Trevor Cox and Peter D'Antonio.

Now, regarding the "transformation" of sound energy to heat, in general, the main mechanisms this can happen are through heat conduction between the various parts of a wave (this is a non-reversible process) and viscosity (especially close to boundaries). These are (usually) called "classical attenuation" but they are not the only ways a sound wave can lose energy. In the second book above as well as Heinrich Kuttruff's book Acoustics - An Introduction you can find a good explanation of the other mechanism that can introduce attenuation. This is encountered in the literature as "molecular attenuation" and is related to the different possibilities a multi-atomic gas can store motion energy (hence heat). The externally provided energy is stored in a translational movement initially. The process of distributing the energy given to the molecule by the external forces in all the different "possibilities", takes some time (relative to the molecular time scale) and is known as molecular relaxation.