translate, decode, encode
譯 centers on converting meaning from one form to another: translating between languages, decoding hidden messages, or encoding information into a different system.
譯 combines 言 (speech, words) with 睪, which likely contributes the sound and relates to the idea of unfolding or interpreting, together suggesting the conversion of meaning through language.
The left side 言 represents words or speech. The right side 睪 looks like a complex mechanism with layers (罒, 辛, 土). Picture words being fed into this intricate machine, which then decodes or encodes them into another language.
For ヤク, imagine a translator working on a yak ranch: yak -> ヤク, and the translator decodes the yak herders' messages.