  In this paper, we propose a novel approach for the transcription of speech
conversations with natural speaker overlap, from single channel recordings. We
propose a combination of a speaker diarization system and a hybrid automatic
speech recognition (ASR) system with speaker activity assisted acoustic model
(AM). An end-to-end neural network system is used for speaker diarization. Two
architectures, (i) input conditioned AM, and (ii) gated features AM, are
explored to incorporate the speaker activity information. The models output
speaker specific senones. The experiments on Switchboard telephone
conversations show the advantage of incorporating speaker activity information
in the ASR system for recordings with overlapped speech. In particular, an
absolute improvement of $11\%$ in word error rate (WER) is seen for the
proposed approach on natural conversation speech with automatic diarization.
