It's an unanticipated result, but it's a unanimous result...

It is a

Details:

This page determines whether "a" or "an" should precede a word. It does this using the method described in this stackoverflow response. The dataset used is the wikipedia-article-text dump. Some additional preprocessing was done to remove as much wiki-markup as possible and extract only things vaguely resembling sentences using regular expressions. If the word following 'a' or 'an' started with a quote or parenthesis, the initial quote or parenthesis was ignored. The resulting prefix-list with the code to query it is less than 10KB in size; excluding the actual counts would reduce the size still further.

Try...

• unanticipated result
• unanimous vote
• honest decision
• honeysuckle shrub
• 0800 number
• xmas tree
• unidirectional beam
• unidiomatic phrase
• NASA scientist
• NSA analyst
• FIAT car
• FAA policy

You may use, modify, redistribute and do whatever you want with the data+script used on this page, but please don't misrepresent its source (license: Apache 2.0). If you've any questions, you can mail me at <firstname>@<lastname>.org.

Downloads:

• .NET nuget package AvsAn (.NET 2.0 or later); you can also manually download binaries from nuget if you prefer.
• JS: Variant including counts of a's and an's : AvsAn.js (12043 bytes, minified+gzipped it's 6333 bytes)
• JS: Variant including only which article is more common: AvsAn-simple.js (4441 bytes, minified+gzipped it's 2299 bytes)
• Source code: on github: EamonNerbonne/a-vs-an. Contributions, bug reports, and pull requests welcome!
• Ruby gem: by Marten Veldthuis, github: marten/a_vs_an.
• node.js package: (alternative implementation by Chad Kirby) github: uplake/Articles

The implementations are efficient: on a single thread of a 3.88GHz i7-4770k a benchmark classifying all words of an english dictionary achieves about 22.5 million words a second; that's just 173 clock cycles per word. The javascript implementations were benchmarked on chrome 35, firefox 32.0a1 (2014-05-22), IE 11, and opera (12 and 21), and are all around 10 times slower, at approximately 4-5 million classifications per second.

--Eamon Nerbonne