This is the descriptive answer.
Google hits
A word of warning about google hits. They are not accurate. Google tries everything to reduce computation time and costs, and it will not give you an accurate full-text search of the entire (public) net. Try going to page 20 or 30, and Google informs you it cannot provide any more results.
Furthermore, a search for 話 is going to turn up many false positives, such as (1) read わ as part of a compound, eg. 対話, and most importantly (2) read はな as part of the word 話す. Searching for 話 includes results such as 話しを.
You should always inspect some of the results manually and look for possible unwanted results.
Trying to avoid these false positives, a google search yields:
面白い話を 9 pages, 460,000 hits面白い話しを 12 pages, 30000 hits
As this is kind of inconclusive, I tried a different corpus.
The noun form 話
A balanced corpus of contemporary written Japanese, searchable via shonagon yields the following results. I add particles before and after 話/話し to avoid false positives.
の話しを 56 resultsの話を 4420 results
And with other particles to make sure these results are not specific to の話を:
の話しに 19 resultsの話に 1496 results
Thus, the spelling 話 for the noun form appears to be about 80 times more frequent than 話し.
話し vs. 話
This article on bunsho-labo gives a prescriptive rule: Use 話し when used as a verb semantically, and 話 when used as a noun.
For example, the correct spelling would be
- 最近、とある女子中学生とお話しをする機会がありました。
- それは、学校生活での悩みに関する話でした。
See the link above for more examples.
The official okurigana rules prescribe added okurigana for nouns nominalized from verbs, but list 話 and several other words as exceptions.
However, the "translation" of the official guidelines for okurigana usage on wikipedia are concerned with semantic extension: Use 話し in the sense of the act of talking, and 話 in the extended sense of story.
I think it can makes a difference in a sentence such as this one taken from the bunsho-labo page above.
PCの向こう側には、彼女が話しをしているときの深刻な表情が浮かぶようでした。
They use 話し because this sentence is about the action, but she might as well be telling a story, which would suggest the non-okurigana form. But never mind grey areas, let us take a look at the actual usage.
Querying the above-mentioned corpus for this distinction:
Therefore, the prescriptive rule does not seem to be observed in written Japanese, at least as far as the form おXをする is concerned, and this form clearly uses it in the sense of 'speaking`.
Furthermore,
お話しを 65 resultsお話をし 238 results
The second search yields about 4 times as many results, even though it is more specific by following 話を with the verb する.
However, regarding the compound 話し言葉, it seems to be the preferred spelling:
話し言葉 129 results話言葉 4 results
Conclusion
At the very least, I cannot find much evidence supporting the rule concerning the distinction in usage between 話し and 話 used as the nominalization speaking in this corpus. If used as a noun talk, the spelling 話 occurs more frequently in this corpus.
Also, as the rule is concerned with the semantic interpretation of the nominalized form and whether it is used in an extended sense, there may be some grey areas.
Note that prescriptive rules exists, be they observed on average or not. In formal writing, you may be well advised to stick to any rules you are expected to follow.
