The current status of the custom language model: * `pending`: The model was created but is
waiting either for valid training data to be added or for the service to finish analyzing added
data. * `ready`: The model contains valid data and is ready to be trained. If the model
contains a mix of valid and invalid resources, you need to set the `strict` parameter to
`false` for the training to proceed. * `training`: The model is currently being trained. *
`available`: The model is trained and ready to use. * `upgrading`: The model is currently being
upgraded. * `failed`: Training of the model failed.