U+A78C Latin Small Letter Saltillo

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In Mexican linguistics, saltillo (Spanish, meaning "little skip") is the word for a glottal stop consonant (IPA: [ʔ]). The name was given by the early grammarians of Classical Nahuatl. In a number of other Nahuan languages, the sound cognate to the glottal stop of Classical Nahuatl is [h], and the term saltillo is applied to it for historical reasons. The saltillo, in both capital and small letter versions, appears in Unicode (in the Latin Extended-D block), but is often written with an apostrophe; it is sometimes written ⟨h⟩ (for either pronunciation), or ⟨j⟩ when pronounced [h]. The spelling of the glottal stop with an apostrophe-like character most likely originates from transliterations of the Arabic hamza. It has also been written with a grave accent over the preceding vowel in some Nahuatl works, following Horacio Carochi (1645).

A glottal stop exists as a phoneme in many other indigenous languages of the Americas and its presence or absence can distinguish words. However, there is no glottal stop in Standard Spanish, so the sound is often imperceptible to Spanish speakers, and Spanish writers usually did not write it when transcribing Mexican languages: Nahuatl [ˈtɬeko] "in a fire" and [ˈtɬeʔko] "he ascends" were both typically written tleco, for example. Where glottal stop is distinguished, the latter may be written tlehko or tleꞌko.