An electronic system for monitoring activity of some echolocating bats in the field is described. An ultrasonic receiver is used to detect the bat cries. Audiofrequency signals from the receiver are processed and converted by the system to characteristic marks on the chart of an event recorder. The utility and limitations of the technique with respect to the echolocating characteristics of bats and analysis of recorder charts are considered. Quantitative data obtained in several habitats with this system are presented.

In infant speech research, children's input in often examined to determine at what age their production is affected by their language experience. In this study, we examined production of stress in Spanish infant-directed speech. Although the correlates of stress in English infant-directed speech have been examined, the same has not been done for Spanish. We analyzed infant-directed speech from eight native Spanish-speaking adults from Central and South America. The infant-directed speech was acquired by recording half-hour sessions of adults interacting in Spanish with 12-month-old infants. The acoustic measures examined to determine stress were: pitch, duration, and intensity. These measures were selected because they have been shown to be the most consistent correlates of stress in Spanish and English adult-directed speech. These measures were taken over a group of six target words: mama, globo, leche, zapato, mira, and agua. These target words allowed us to examine each of the vowels (/a/, /e/, and /o/) in both stressed and unstressed position, as well as in varying word positions. With these data we hope to discover how stress is instantiated in Spanish infant-directed speech in order to provide a baseline for future investigations of babbling by Spanish-learning infants.

Research on Spanish prosody in adult-directed speech (ADS) (Ortega-Llebaria & Prieto 2005, Ortega-Llebaria & Prieto 2011) shows evidence for three acoustic levels of prominence: stressed and focused, stressed and unfocused, and unstressed and unfocused. We tested whether Spanish infant-directed speech (IDS) contains the same levels of prosodic prominence as ADS. In order to test this hypothesis, 30-minute play sessions between adult Spanish-speaking females of Latin American origin (n = 12) and 12-month old infants were recorded. We extracted target words from the recordings containing stressed and unstressed /a/, /e/, /i/, and /o/ in non-final position. Voicesauce (Shue et al 2011) was then used to obtain acoustic correlates of stress in Spanish: pitch, duration, intensity. We also labeled pitch accents using SpToBI conventions (Estebas Vilaplana & Prieto 2009). Latent class analyses to be performed on the data will determine the number of distinct prominence levels present in Spanish IDS as realized by Latin American speakers.