def METHOD_NAME(filename, language='en'):
    """Loads a single training data file from disk."""
    fformat = _guess_format(filename)
    if fformat == UNK:
        raise ValueError("Unknown data format for file {}".format(filename))
    logger.info("Training data format of {} is {}".format(filename, fformat))
    reader = _reader_factory(fformat)
    if reader:
        return reader.read(filename, language=language, fformat=fformat)
    else:
        return None