Both REST and web search seem to be missing large number of tweets if searched phrase includes Turkish capital “I”. This becomes very interesting when topic is trending for example I’ve even seen some cases where clicking on the tag from trending topic list returned zero results which is a “weird” experience for sure.
To help understanding this better check below trending topic which was on the list for Turkey starting at 2014-09-17 19:38:00 UTC.
Trending topic was: “IzmirliOlmak PahaBicilemez”
Direct link to search is as https://twitter.com/search?q=IzmirliOlmak%20PahaBicilemez&src=typd which results with couple of tweets. A trending topic with couple of tweets not expected right?
On the other hand searching with lower case “ı” seems to help on the same phrase: https://twitter.com/search?q=ızmirliOlmak%20PahaBicilemez&src=typd
Can you please investigate this issue? Turkish “I” is a very common letter and the issue is severing very high number of search experiences.