12. The method of claim 1 wherein the MD-GMM comprises a key child model; modifying the key child model using an age-dependent key child model; and wherein segmenting the audio recording into the plurality of segments and identifying the segment ID for at least one of the plurality of segments using the MD-GMM comprises using the MD-GMM comprising the modified key child model.
1. A method comprising: capturing an audio recording from a language environment of a key child, segmenting the audio recording into a plurality of segments; identifying a segment ID for each of the plurality of segments, the segment ID identifying a source for audio in the segment, wherein segmenting the audio recording into the plurality of segments and identifying the segment ID for each of the plurality of segments comprises using a Minimum Duration Gaussian Mixture Model (MD-GMM), and wherein the segments identified using the MD-GMM are at least a minimum duration D, and any segments with a duration longer than 2*D are broken down into several segments with a duration between D and 2*D; estimating key child segment characteristics based in part on at least one of the plurality of key child segments, wherein the key child segment characteristics are estimated independent of content of the plurality of key child segments, wherein the content is the meaning of the plurality of key child segments; determining at least one metric associated with the language environment using the key child segment characteristics; and outputting the at least one metric.