Citations:転呼音

Use in English as Tenko

 * Historical kana usage:How to read
 * Some kana are read with different sounds instead of their original sounds under a certain condition. These phenomena are called Tenko(Change of call).
 * (emphasis added)
 * Kobun (Classical Japanese) - Old Kana: Why the "Ye" in "Yebisu" is even a Thing
 * Below you'll find bulleted lists of Tenko -"change of call".
 * The Tenko rules above are for the middle of words, so 我 is still "ware", and 昔 still "mukashi."
 * These are the other Tenko trends:
 * (emphasis added)

It is noteworthy that the first source was originally written in Japanese and translated by someone associated with the site to English, while the second was written by native English speakers for native English speakers. It is possible that an erroneous Japanese-to-English translation is the origin of this usage.