1. A method for evaluating one or more spoken language skills of a speaker, comprising the steps of: identifying one or more temporal locations of interest in an output of a spoken language skill evaluation performed on a speech passage spoken by a speaker; computing one or more acoustic parameters to capture one or more properties of one or more acoustic-phonetic features of the one or more locations of interest, said computing comprising determining one or more spectral differences between the onset of a fricative, a vowel and a stop burst by computing a ratio of energy in a high frequency region of the speech passage to energy in a low frequency region of the speech passage over a predetermined time period via 1 N f ⁢ ∑ f = 1 N f ⁢ [ Δ ⁡ ( f , l ) - μΔ , l ] 2 , wherein f is a given frequency channel, N f is a total number of frequency channels, l is a given frame number, Δ(f, l) is an energy difference in adjacent frames for the given frequency channel f, and μΔ,l is the mean of Δ (f, l) over all frequency channels for the given l; and combining the one or more acoustic parameters with the output of an automatic speech recognizer to generate a modified output of the spoken language skill evaluation.