In this chapter, we have shown how to develop simple voice interactions using the Google speech recognition and TTS APIs. The first example showed how to take an input of some words from the user and initiate a search query. The second example involved using speech to launch apps on the device. Here we introduced the technique of using similarity measures to compare the recognition of the user's input with what might have been said. Two different measures were illustrated: orthographic similarity and phonetic similarity. The final example showed how to use confirmations in order to check with the user that the system had recognized the input correctly. These techniques, along with the use of confidence scores introduced in the previous chapter, are useful tools for the development of speech-enabled apps.
However, these interactions are limited in two ways. Firstly, they do not involve the use of dialog state information to control the interaction and to determine what the app should...