As far as I understand, only the use of the attention mechanism with ConvNets is novel, right? Convolutional encoders have been done before.
Yes, there have been a couple of attempts to use CNNs for translation already, but none of them outperformed big and well-tuned LSTM systems. We propose an architecture that is fast to run, easy to optimize and can scale to big networks, and could thus be used as a base architecture for future research. There are a couple of contributions in the paper ( https://arxiv.org/abs/1705.03122 ) apart from demonstrating the…
It is true that QRNN had results on mostly small-scale benchmarks, but it seemed that Bytenet especially the second version had SOTA results both for language models with characters and for machine translation with characters on the same large-scale En-De WMT task that is used in this paper.
MT with characters, with regards to ordering, structure, etc, is potentially much harder than with words or word-pieces, since the encoded sequences are 5 or 6 times longer on average, and the meanings of words need to be built up from individual characters.