Blurb:

Locus equations were employed to phonetically describe the degree of CV coarticulation as a function of speaking style. Two male speakers of Persian participated in this study. C1VC2 tokens were produced in citation-style laboratory speech as well as informal spontaneous speech characterized by hypo-articulation, where C1 was one of the voiced stops /b,d,ɟ,G/ and V was one of the six simple vowels /i,e,a,u,o,ɑ/. In both styles, locus equation slopes were highest for /ɟ/ and /G/, intermediate for /b/, and lowest for /d/. Locus equations slope values increased for /d, ɟ, G/ in spontaneous relative to citation style, but remained relatively stable for /b/. Results indicate increased coarticulation in informal spontaneous speech for consonants involving the tongue as the main articulator. For bilabial place of articulation coarticulatory overlap is already at its maximum in citation style, which cannot increase further under the conditions imposed by hypo-articulation.