Implications of Sepedi/English code switching for ASR systems

Code switching (the process of switching from one language to another during a conversation) is a common phenomenon in multilingual environments. Where a minority and dominant language coincide, code switching from the minority language to the dominant language can become particularly frequent. We analyse one such scenario: Sepedi spoken in South Africa, where English is the dominant language; and determine the frequency and mechanisms of code switching through the analysis of radio broadcasts. We also perform an initial acoustic analysis to determine the impact of such code switching on speech recognition performance. We find that the frequency of code switching is unexpectedly high, and that the continuum of code switching (from unmodified embedded words to loan words absorbed in the matrix language) makes this a particularly challenging task for speech recognition systems.