14. A system comprising: a recorder adapted to capture audio recordings from a language environment of a key child; a processor-based device, wherein the recorder provides the audio recordings to the processor-based device, and the processor-based device comprising an application having an audio engine adapted to segment the audio recording into a plurality of segments and identify a segment ID for each of the plurality of segments, wherein at least one of the plurality of segments is associated with a key child segment ID, wherein the audio engine segments the audio recording and identifies a segment ID for each of the plurality of segments 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, the audio engine being further adapted to: estimate key child segment characteristics based on the at least one of the plurality of segments, wherein the audio engine estimates key child segment characteristics independent of content of the at least one of the plurality of segments, wherein the content is the meaning of the plurality of key child segments; determine at least one metric associated with the language environment using the key child segment characteristics; and output the at least one metric to an output device.
18. The system of claim 14 wherein the audio engine uses the MD-GMM by: scoring each of the plurality of segments using log-likelihood scoring and a plurality of models; and analyzing the scored plurality of segments to assign the segment ID to each of the plurality of segments.