Usually you need to calculate your own word frequencies from your own corpus. Very large corpora are better but of course this takes a lot of work, space, time, etc, and distracts from the task at hand.
I'm wondering if there are any Web API providers that have done all this for you and provide programmatic access to frequency data via the web.
- English is a must, other languages are a big plus.
- Gratis is better than paid, open is better than closed.
- Optional stemming and/or lemmatization would be a plus but not required.
- Any requirements for registration, throttling, daily limits, etc are OK.
- Any format is OK but urlencoded and JSON are expected.
- Unicode support is a very strong preference. (Should not blow up on words like café, naïve, etc.)