I. Introduction  
II. Acoustic Devices and Channels  
A. Acoustic Hardware  
B. Acoustic Channel Properties  
C. Acoustic Platforms  
D. Challenges  
III. Core Acoustic Sensing Techniques  
A. Waveform Design  
B. Temporal Feature Extraction  
C. Channel Profiling  
IV. Acoustic Sensing Applications  
A. Aerial Acoustic Communication  
B. Applications Leveraging Temporal Features  
C. Solutions Enabled by Channel Characteristics  
V. Future Directions  
A. Privacy and Security Threats  
B. Repurposing Other Sensors for Acoustic Sensing  
C. Earable Computing  
D. Benchmark Datasets and Platforms  
VI. Conclusion