An end-to-end approach [1] [2] [3] [4] <cite>[5]</cite> [6] [7] is particularly appealing for source languages with no written form, or for endangered languages where translations into a high-resource language may be easier to collect than transcriptions [8] . However, building high-quality endto-end AST with little parallel data is challenging, and has led researchers to explore how other sources of data could be used to help.