Debuccalization of /s/ to [h]

Question

What is meant in Spanish phonology by the debuccalization of /s/ to [h]? What dialects does this phenomenon primarily occur in? In those dialects, does it take place in all cases or only in some environments?

Answer 1

Debuccalization is a sound change that consists in a consonant losing its original place of articulation becoming [h] o [ʔ].

Saying place of articulation, we mean one of these:

1. Exo-labial, 2. Endo-labial, 3. Dental, 4. Alveolar, 5. Post-alveolar, 6. Pre-palatal, 7. Palatal, 8. Velar, 9. Uvular, 10. Pharyngeal, 11. Glottal, 12. Epiglottal, 13. Radical, 14. Postero-dorsal, 15. Antero-dorsal, 16. Laminal, 17. Apical, 18. Sub-apical

To see what and where are these "places", check this scheme on Wikipedia; (the numbers on this list correspond to the numbers in that scheme.)

In most places of South America (except Mexico, guatemalan plateau, Costa Rica, andean Venezuela, Quito and ecuadorian plateau¹, bolivian plateau and Bogotà) and in half of the southern Spain, the s in the last position of a syllable is an aspirated (a voiceless glottal fricative, /h/, that is, debuccalization) or sometimes not pronounced at all in some variants of the current language. For example, see the following sentence:

Todos los cisnes son blancos.

It can be pronounced as [todɔh lɔh sihnɛh sɔm blankɔh] or as [todɔ lɔ sinɛ sɔm blankɔ]

Standard Spanish pronunciation: [ˈto̞ðo̞z lo̞s ˈθizne̞s sõ̞m ˈblãŋko̞s]

In the eastern Andalusia and in the Murcia region, the distinction between syllables with silent s and those originally without s has been preserved in the pronunciation of syllables ending in s with open vowels (that is, the contrast between open and closed syllable turned into a tense/lax vowel contrast. This typically affects the vowels /a/, /e/ and /o/, but in some areas even /i/ and /u/ have, in effect, a double set of phonemes.

^{Source: italian and english wikipedia page.}

<sup>Notes:
1. plateau: upland, mesa.</sup>