Rather, glottalization usually means that a normal pulmonic airstream is partially or completely interrupted by closure of the glottis.
There are three ways this can be represented in the International Phonetic Alphabet: (a) with an apostrophe; (b) with a superscript glottal stop; or (c) with an under-tilde.
Among the three classes of these consonants as defined above, ejectives are more widely found than implosives, and glottalized resonants are the least widespread.
Maddieson says, “They are particularly found along the Andean cordillera in the south, in Mexico and Guatemala, and in the more northwesterly parts of North America.
Most strikingly, the consonant inventories of almost all the diverse indigenous languages of northern California, Oregon and Washington, British Columbia, the Yukon and Alaska include ejectives.” Clusters elsewhere include the Semitic languages of Ethiopia and neighbouring countries.
Glottalized resonants are found only in three languages with ejectives outside the Western Hemisphere; Maddieson suggests, “The association between glottalized resonants and ejectives might best be viewed as a result of overlapping patterns of spread in a single area, and not as the consequence of any particular linguistic dependence between the occurrence of these two classes of consonants.” Maddieson believes that complex consonants, requiring "more intricate coordination" of different parts of the mouth and throat, are more likely to occur in languages with larger numbers of contrasting consonant phonemes.