It's intentionally made to be hard to listen to. OP spliced multiple copies together with a slight offset, varied the rate while recording, and intentionally selected a passage which repeats very similar words in proximity, which further increases the difficulty.

> Formant synthesis does not use human speech samples at runtime. Instead, the synthesized speech output is created using additive synthesis and an acoustic model (physical modelling synthesis. Parameters such as fundamental frequency, voicing, and noise levels are varied over time to create a waveform of artificial speech. This method is sometimes called rules-based synthesis; however, many concatenative systems also have rules-based components.