First of all - contratulations on an excellent app. So much better than the ones I had been using. Partly due to the rich and varied cowd sourced data, but also Christian did a great job on the interface.
I only discovered it this week and downloaded it onto an iPhone 4s running iOS 7.1.0. I have had the issue with the app crashing unexpectedly. Mostly this seems to be after multiple searches, and going back to type in the search box quickly. The iPhone struggled to keep up with the typing and then the app crashes.
However, the iOS 7.1.1 update says that it deals with the keyboard lag issue, which it does appear to be doing. So far I haven't had any crashes with your app on 7.1.1, so hope this will help others too.
One other issue that doesn't appear to have been fixed in 7.1.1 is the use of Apple's "enhanced quality" voice. I use this to read out example sentences in Thai from your app. Clicking and holding on the sentence then choosing "speak" will read out the sentence. However, the quality of the default sythesised voice is pretty poor. This can be improved in settings by selecting the enhanced quality voice and downloading 59.2GB of extra voice files. However, your app seems to only use the default voice. In addition, it ignores the "speaking rate" setting for the voice (I want it really slow!). Looks to me like these could be iOS problems as well, unless it is the way the voice API is implemented.
Would be really grateful to be able to use the enhanced quality voice at a my chosen speed.
Thanks
Sherratt