... 12,742 Table 1. Modeling statistics The most common metric for evaluating an n-gram model is the probability that the model assigns to test data, or perplexity (Jelinek, 1991). For a test set ... source-channel model by fully exploring orthographic contextual information, aiming at alleviating the imprecision introduced by the multiple-step phoneme-based approach. 3 Joint source-channel model ... sufficient for every n-gram unit, different smoothing approaches are applied, for example, by using backoff or class-based models, which can be found in statistical language modeling literatures...