Spanish Closure Not Binary

In Spanish /b, d, g/ are described as stops in some contexts and approximates (i.e. voiced fricatives with vowel-like qualities) in others. Rather than accept this binary division Professor Eddington used measurements of intensity to get a continuous measure of closure, finding that these stops are more vowel-like between vowels and most stop-like after a pause. However, post-nasal and post-lateral instances fall between these extremes. In addition, they are also more stop-like when following [s] or [h]. When followed by a stressed syllable, /b/ and /d/ exhibit more constriction when compared to /g/, while all three phones are less closed when they fall between two stressed syllables. /b/ and /d/ are also more constricted when they appear intervocalically in word-initial position when compared to word-internal intervocalic tokens, while the same is not true for /g/. Contra traditional descriptions,  /d/ is no less open than /b/ or /g/ following a lateral. Instances of /d/ are also less constricted when they appear in high frequency words and more constricted in low frequency words. On the other hand, frequency is not a factor for /b/ and /g/.

Probus. Volume 23, Issue 1, Pages 1–19