def altimeter(alt: Number, unit: str = 'inHg') -> str:
    """
    Format altimeter details into a spoken word string
    """
    ret = 'Altimeter '
    if not alt:
        ret += 'unknown'
    elif unit == 'inHg':
        ret += core.spoken_number(alt.repr[:2]) + ' point ' + core.spoken_number(alt.repr[2:])
    elif unit == 'hPa':
        ret += core.spoken_number(alt.repr)
    return ret