Final answer:
Consonants are classified by voicing, place of articulation, and manner of articulation. These criteria determine how the vocal cords, the vocal tract, and airflow are employed to produce consonant sounds.
Step-by-step explanation:
Three pieces of information that classify consonants are voicing, place of articulation, and manner of articulation. Voicing determines whether the vocal cords vibrate when producing the consonant sound. The place of articulation is the point in the vocal tract where the airflow is restricted, such as the lips, teeth, or back of the throat. Lastly, the manner of articulation refers to how the airflow is restricted, whether it's a complete closure, as in plosives like [p] and [t], or a partial closure as in fricatives like [f] and [sh]. Other aspects of speech, such as vowel quality,, and the schwa sound, also play important roles in phonetics and the classification of sounds, but they do not classify consonants.