  Developing Automatic Speech Recognition (ASR) for low-resource languages is a
challenge due to the small amount of transcribed audio data. For many such
languages, audio and text are available separately, but not audio with
transcriptions. Using text, speech can be synthetically produced via
text-to-speech (TTS) systems. However, many low-resource languages do not have
quality TTS systems either. We propose an alternative: produce synthetic audio
by running text from the target language through a trained TTS system for a
higher-resource pivot language. We investigate when and how this technique is
most effective in low-resource settings. In our experiments, using several
thousand synthetic TTS text-speech pairs and duplicating authentic data to
balance yields optimal results. Our findings suggest that searching over a set
of candidate pivot languages can lead to marginal improvements and that,
surprisingly, ASR performance can by harmed by increases in measured TTS
quality. Application of these findings improves ASR by 64.5\% and 45.0\%
character error reduction rate (CERR) respectively for two low-resource
languages: Guaran\'i and Suba.
