How do glottal stops occur in Indigenous North American languages?

In many Indigenous North American languages, the glottal stop functions as a distinct phoneme, serving as a common consonant that interrupts breath by closing the vocal cords.12

Beyond the simple glottal stop, many languages in western North America utilize glottalized consonants. These are produced through a mechanism distinct from the lung-based airflow used in English. Instead, the glottis is closed and raised, trapping air above the vocal cords; this air is then ejected when the primary oral closure for the consonant is released.2

This feature is often represented in writing with an apostrophe and is essential for distinguishing word meanings. For example, in the Hupa language, the presence of a glottalized consonant differentiates teew (underwater) from t’eew (raw). Additionally, the process of glottalization can involve the partial or complete closure of the glottis occurring before, during, or after the primary articulation of a sound, and it may also apply to vowels in various Indigenous languages.21