Automatic call-routing without transcriptions

Call-routing is now an established technology to automate customers’ telephone queries. However, transcribing calls for training purposes for a particular application requires considerable human effort, and it would be preferable for the system to learn routes without transcriptions being provided. This paper introduces a technique for fully automatic routing. It is based on firstly identifying salient acoustic morphemes in a phonetic decoding of the input speech, followed by Linear Discriminant Analysis (LDA) to improve classification. Experimental results on an 18 route retail store enquiry point task using this technique are compared with results obtained using word-level transcriptions.