Interspeech posture (ISP) is a term used to define the position of a person’s articulators when they are preparing to speak. Research suggests that ISP may be representative of a speaker’s phonological knowledge in a particular language, as determined empirically with ultrasound measures of the tongue in English-French bilinguals (Wilson & Gick, 2014). It is possible, therefore, that measuring ISP could be a diagnostic tool for determining phonological knowledge in bilingual speakers. However, more information on ISP in typical adult bilingual speakers is needed before diagnostic claims can be made. For example, ISP is believed to be language specific, and the typical ISP for each language must be determined. Therefore, the purpose of this study was to extend the research by Wilson and Gick (2014) to investigate ISP in Spanish-English speaking adults. To this end, 13 bilingual Spanish-English adults were asked to produce 30 sentences while speaking in monolingual and bilingual modes. While they were speaking, ultrasound images of the oral cavity were obtained by placing a probe sub-mentally and analyzing the position of the tongue using Articulate Assistant Advanced 2.0 software (Articulate Instruments, 2012). Tongue and palate contour measurements were made by using a curved tongue spline that was manually drawn and semi-automatically fit to each speaker’s tongue/palate contour. ISP was measured using the participant’s tongue tip height along a reference angle from the probe to the alveolar ridge. Additionally, monolingual English speaking adults were asked to rate the accentedness of each bilingual’s speech in English as a behavioral correlate of language proficiency. Overall results of this study were non-significant; bilingual Spanish-English speakers utilized similar postures in monolingual Spanish and English modes, and in bilingual mode, in contrast with the findings of Wilson and Gick (2014). Accentedness ratings in English v indicated that the bilingual speakers were relatively uniform in their lack of accentedness. Although overall results from this study differ from those of Wilson and Gick (2014) a subset of their participants- speakers that were rated as having non-native accents- had similar results in that they also showed no difference in ISP. Related ISP’s across languages may be due to participants having native sounding English but non-native Spanish. Due to contrasting findings from Wilson and Gick (2014), further investigation with accented speakers is needed to determine if distinct ISPs exist for bilingual Spanish-English speakers.