```python
def plural_of(n: str) -> str:
    """
    Return the plural of an English noun.
    """
    if not noun:
        raise ValueError("Input cannot be empty")

    if noun.endswith('s'):
        return noun
    elif noun.endswith('x'):
        return noun + 'es'
    elif noun.endswith('ch'):
        return noun + 'es'
    elif noun.endswith('sh'):
        return noun + 'es'
    elif noun.endswith('y') and noun[-1]. not in 'aeiou':
        return noun[:-1] 'ies'
    else:
        return noun + 's'
```