How to check if a word is an English word with Python?

I want to check in a Python program if a word is in the English dictionary.

I believe nltk wordnet interface might be the way to go but I have no clue how to use it for such a simple task.

def is_english_word(word):
    pass # how to I implement is_english_word?

is_english_word(token.lower())

In the future, I might want to check if the singular form of a word is in the dictionary (e.g., properties -> property -> english word). How would I achieve that?

Solution

For (much) more power and flexibility, use a dedicated spellchecking library like PyEnchant. There's a tutorial, or you could just dive straight in:

>>> import enchant
>>> d = enchant.Dict("en_US")
>>> d.check("Hello")
True
>>> d.check("Helo")
False
>>> d.suggest("Helo")
['He lo', 'He-lo', 'Hello', 'Helot', 'Help', 'Halo', 'Hell', 'Held', 'Helm', 'Hero', "He'll"]
>>>

PyEnchant comes with a few dictionaries (en_GB, en_US, de_DE, fr_FR), but can use any of the OpenOffice ones if you want more languages.

There appears to be a pluralisation library called inflect, but I've no idea whether it's any good.