Microsoft Web N-Gram Service

Microsoft has developed services on the basis of ngrams from all of Bing's en_US corpus. The raw public data available include two files with the top 100k words from this corpus.

The documentation to Its API introduces the service as:

The Microsoft Web N-Gram service currently provides two services for the community, Lookup and Generate. The former allows users to look up the probability of words, and the latter allows users to get a list of words for which we have probability data.

The team also provides a word splitting API, that will try to seperate thisfromthat to this from that.

Access to these services is free, but requires acceptance of custom terms of use.