Ambient noise (e.g., rustling, line noise, interference) Noisy environments (e.g., streets, bars, restaurants, or other types of background noise) Speakers who are recorded from a distance (e.g., ambiguous, distant voices) Speakers with a strong non-American accent (e.g., British, Australian, Indian, Hispanic, and other non-American speakers) Interruptions in the recording (e.g., poor phone line, gaps in