How do tones distinguish meaning in Otomanguean languages?

Many Otomanguean languages utilize a complex system of pitches or intonations to distinguish between words that are otherwise identical in their sequence of consonants and vowels.1

In these languages, pitch serves as a phonemic feature where the relative pitch level or the direction of a pitch change within a syllable functions to differentiate meaning. By using a limited number of pitch contrasts, speakers can alter the definition of a word simply by changing the tone, effectively creating distinct lexical items from the same phonetic base.23