Question: Is there an api for Speech to text for windows 8.1 universal apps? Even a web service would work, as long as it supports Japanese.

Answer: 
You may use SpeechRecognizerUX class. Details are at <https://msdn.microsoft.com/en-us/library/dn434633.aspx>
An alternative method is at <https://code.msdn.microsoft.com/windowsapps/Speech-Recognition-19c452b4>
You may refer to this <https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/SpeechRecognitionAndSynthesis>

this sample covers the following scenarios:

1.Synthesizing text to speech (TTS)
2.Synthesizing Speech Synthesis Markup Language (SSML)
3.One-shot recognition using the predefined dictation grammar
4.One-shot recognition using the predefined webs search grammar
5.One-shot recognition using a custom list-based grammar
6.One-shot recognition using a custom SRGS/GRXML grammar
7.Continuous dictation
8.Continuous recognition using a custom list-based grammar
9.Continuous recognition using a custom SRGS/GRXML grammar
10.Pausing and resuming continuous recognition

In addition, translations are shown for speech recognition and text-to-speech for supported languages. Translations provided may not be using ideal phrasing and are provided for demonstration purposes only.

```
 synthesizer = new SpeechSynthesizer();

        speechContext = ResourceContext.GetForCurrentView();
        speechContext.Languages = new string[] { SpeechSynthesizer.DefaultVoice.Language };

        speechResourceMap = ResourceManager.Current.MainResourceMap.GetSubtree("LocalizationTTSResources");

```