1. A computer-implemented method comprising: under control of one or more computing devices configured with specific computer-executable instructions, obtaining audio data of an utterance; generating, using the audio data, a first feature stream comprising one or more feature vectors, wherein individual feature vectors of the first feature stream comprise statistical values computed for a corresponding portion of the audio data; generating, using the audio data, a second feature stream comprising one or more feature vectors, wherein individual feature vectors of the second feature stream comprise statistical values computed for a corresponding portion of the audio data; generating a first transformed vector using an affine transformation and a feature vector of the first feature stream; generating a second transformed vector using a non-linear feature transformation and a feature vector of the second feature stream; adding the first transformed vector to the second transformed vector to generate a combined vector; generating a maximum value vector by selecting, for at least one value of the maximum value vector, a maximum value from a set of values comprising a value of the first transformed vector and a corresponding value of the combined vector, wherein a lower corresponding value of the combined vector relative to the value of the first transformed vector is indicative of corrupted data in the combined vector; determining a phoneme that corresponds to a portion of the audio data, wherein if the first value is the maximum value, the phoneme is determined based at least partly on the first transformed vector, and wherein if the second value is the maximum value, the phoneme is determined based at least partly on the combined vector; and generating speech recognition results using the phoneme and a language model, wherein generating the speech recognition results comprises: generating a set of phonemes comprising the phoneme; and applying the language model to the set of phonemes to generate a likely transcription of the utterance.