A score that shows how much a transcript differs from the correct words.
WER is like a strict spelling-test teacher with one red pen. Every wrong, missing, or random extra word costs points.
It tests speech-to-text and captions. A lower WER means the transcript is closer to the real words.
ASR
ASR uses WER to show how many words the transcript got wrong.
STT
When STT matches the real words better, WER goes down.
CTC
CTC often trains speech models, and WER can check their output.