add LENA AVA stats

[tjmahr]

LENA's automatic vocalization assessment tries to measure the child's expressive language development from a recording by analyzing the biphones in the child's speech.

AVA software uses automatic speech recognition technology to categorize and quantify the sounds in child vocalizations (e.g., protophones and phonemes). These quantitative acoustic information data (expressed as “phone” and “biphone” frequencies) are reduced to principal components which are applied as input for age-based multiple linear regression models. The AVA software utilizes these regression models to generate information about expressive language development as standard scores, developmental age estimates, and estimated mean length of utterance (EMLU). [source]

These are included in the XML files created by LENA, so the data just needs to be extracted and databased.