7. The method of claim 1 , wherein the first criterion comprises determining whether the average frame likelihood β r of the retained audio file satisfies the criterion β r ≧δ+Δ, where Δ is a first predetermined threshold, and wherein the second criterion comprises determining whether the phoneme recognition accuracy γ g of the retained audio file satisfies the criterion γ g ≧v+μ, where μ is a second predetermined threshold.
7. The method of claim 1 , wherein the first criterion comprises determining whether the average frame likelihood β r of the retained audio file satisfies the criterion β r ≧δ+Δ, where Δ is a first predetermined threshold, and wherein the second criterion comprises determining whether the phoneme recognition accuracy γ g of the retained audio file satisfies the criterion γ g ≧v+μ, where μ is a second predetermined threshold. 8. The method of claim 7 , wherein Δ=−0.1δ.